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v2.4.1.9

Fair Value Measurements - Summary of Changes in Level 3 Fair Value Category (Detail) (USD $) In Thousands, unless otherwise specified | 8 Months Ended | 12 Months Ended | 4 Months Ended | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2014 | Apr. 30, 2013 | Dec. 31, 2012 | Dec. 31, 2013
Successor [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | $ 69,412 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | $ 67,783 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Included in earnings | 1,870 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 11,057 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 7,184 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (541)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases |  | 54,013 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | (4,528)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (59,878)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (6,428)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (62,266)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 273 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 188,241 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (208)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | 67,783 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 198,201 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 67,783 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Successor [Member] | Derivatives by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | (415,360)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (186,934)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Included in earnings | 217,666 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (45,392)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | 10,760 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 16,980 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | (186,934)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (215,346)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | (186,934)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date | (91,436)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 53,509 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Successor [Member] | Asset-backed Securities [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 61,782 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 64,073 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |  |  |
Included in earnings | 1,912 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 6,994 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 7,315 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | (8,182)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | (4,528)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | (59,878)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (2,408)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | (3,007)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |  |  |
Balance, end of period | 64,073 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |  |  | 64,073 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember
Successor [Member] | U.S. Agency Obligations [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  | 208 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |
Included in earnings | (5)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 5 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (65)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 273 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  | (208)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |
Balance, end of period | 208 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |  |  |  | 208 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Successor [Member] | Non-Agency RMBS [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = ambc_NonAgencyRMBSMember |  |  |
Included in earnings |  | 4,160 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = ambc_NonAgencyRMBSMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  | 7,238 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = ambc_NonAgencyRMBSMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases |  | 54,013 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = ambc_NonAgencyRMBSMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  | (59,259)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = ambc_NonAgencyRMBSMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  | 188,241 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = ambc_NonAgencyRMBSMember |  |  |
Balance, end of period |  | 194,393 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember / us-gaap_UnderlyingAssetClassAxis = ambc_NonAgencyRMBSMember |  |  |
Successor [Member] | Collateralized Debt Obligations [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 3,949 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Included in earnings | 25 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | (19)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (3,955)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Successor [Member] | Corporate Obligations [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 3,681 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 3,502 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Included in earnings | (62)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (97)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | (117)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 403 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | 3,502 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 3,808 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 3,502 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Successor [Member] | Interest Rate Swaps [Member] | Derivatives by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | (137,947)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (92,612)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Included in earnings | 24,797 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (69,298)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | 20,538 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 20,023 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | (92,612)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (141,887)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | (92,612)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date | (24,797)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 69,298 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Successor [Member] | Credit Derivatives [Member] | Derivatives by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | (277,413)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (94,322)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Included in earnings | 192,869 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 23,906 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (9,778)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (3,043)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | (94,322)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (73,459)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | (94,322)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date | (66,639)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (15,789)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Predecessor [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 60,402 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 97,522 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 60,402 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | (33)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (3)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 12,329 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 7,485 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (3,286)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (97,206)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  |  | 58,905 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  |  | (6,301)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 69,412 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 60,402 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Predecessor [Member] | Derivatives by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | (322,337)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (486,775)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (322,337)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Additions of VIEs consolidated |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Included in earnings |  |  | (88,546)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 21,076 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (4,477)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (48,886)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 192,248 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Deconsolidation of VIEs |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | (415,360)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (322,337)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | 92,002 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 113,836 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Predecessor [Member] | Asset-backed Securities [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 50,264 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 75,886 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 50,264 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 12,117 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 7,051 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (599)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | (85,741)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  |  | 53,068 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |
Balance, end of period |  |  | 61,782 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember | 50,264 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_AssetBackedSecuritiesMember |
Predecessor [Member] | U.S. Agency Obligations [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember | 1,224 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Included in earnings |  |  |  | (2)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  |  | (9)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  | (749)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  |  | (464)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
Balance, end of period |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember / us-gaap_UnderlyingAssetClassAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
Predecessor [Member] | Collateralized Debt Obligations [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 6,482 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 12,482 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 6,482 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | (6)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (5)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 160 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 646 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (2,687)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (6,641)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 3,949 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 6,482 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CollateralizedDebtObligationsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Predecessor [Member] | Corporate Obligations [Member] | Investment by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 3,656 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 7,930 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 3,656 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | (27)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 4 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 52 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (203)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  | (4,075)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  |  | 5,837 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  |  | (5,837)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 3,681 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 3,656 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_InvestmentTypeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Predecessor [Member] | Interest Rate Swaps [Member] | Derivatives by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | (108,752)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (302,177)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (108,752)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Additions of VIEs consolidated |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Included in earnings |  |  | (28,162)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (70,415)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (1,033)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 71,592 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 192,248 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Deconsolidation of VIEs |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | (137,947)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (108,752)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | 28,162 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 78,505 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_InterestRateSwapMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Predecessor [Member] | Credit Derivatives [Member] | Derivatives by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | (213,585)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (190,653)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (213,585)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Additions of VIEs consolidated |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Included in earnings |  |  | (60,384)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (9,219)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (3,444)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (13,713)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Deconsolidation of VIEs |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | (277,413)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (213,585)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | 63,840 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 35,331 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CreditDerivativeMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Predecessor [Member] | Call Options on Long-Term Debt [Member] | Derivatives by Class [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  |  | 6,055 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Additions of VIEs consolidated |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Included in earnings |  |  |  | 100,710 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  |  | (106,765)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Deconsolidation of VIEs |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  |  | 0 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FinancialInstrumentAxis = us-gaap_DerivativeMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_CallOptionsonLongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Level 3 [Member] | Successor [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 15,170,359 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 14,253,705 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Included in earnings | (417,184)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 1,221,057 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 955,046 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (822,098)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 124,013 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | (4,528)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (59,878)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (42,381)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (403,576)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | (220,649)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 188,241 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 365,046 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 3,888 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Deconsolidation of VIEs | (1,552,004)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (659,898)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | 14,253,705 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 13,845,454 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 14,253,705 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  | (1,207,070)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 565,205 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Level 3 [Member] | Successor [Member] | Investments Contract [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 2,500,565 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 2,475,182 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Included in earnings | (178,322)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 429,113 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 152,939 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (161,245)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Balance, end of period | 2,475,182 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 2,743,050 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 2,475,182 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  | (429,113)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 178,322 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Level 3 [Member] | Successor [Member] | Loans [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 14,752,053 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 13,398,895 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Included in earnings | (455,231)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 1,118,084 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 873,986 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (726,827)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 70,000 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (219,909)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (792,186)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Deconsolidation of VIEs | (1,552,004)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (696,789)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | 13,398,895 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 12,371,177 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 13,398,895 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  | (1,119,219)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 475,152 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Level 3 [Member] | Successor [Member] | Long-Term Debt [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | (1,750,372)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (1,514,605)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Included in earnings | (2,490)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (290,457)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | (79,063)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 66,515 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | 173,196 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 433,896 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | (220,922)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 365,046 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 4,096 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 36,891 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Balance, end of period | (1,514,605)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (1,263,664)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | (1,514,605)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  | 286,405 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 2,490 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Level 3 [Member] | Successor [Member] | Investments [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 69,412 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 67,783 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Included in earnings | 1,870 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 11,057 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 7,184 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (541)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 54,013 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | (4,528)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (59,878)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | (6,428)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (62,266)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 273 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 188,241 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (208)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Balance, end of period | 67,783 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 198,201 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 67,783 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  |  |  | 0 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Level 3 [Member] | Successor [Member] | Other Assets [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | 14,061 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 13,384 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Included in earnings | (677)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (1,348)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Balance, end of period | 13,384 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 12,036 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 13,384 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  | 1,348 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | 677 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Level 3 [Member] | Successor [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period | (415,360)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (186,934)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Additions of VIEs consolidated | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Included in earnings | 217,666 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (45,392)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Purchases | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityPurchases / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Sales | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySales / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements | 10,760 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 16,980 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Deconsolidation of VIEs | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Balance, end of period | (186,934)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (215,346)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | (186,934)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  | 53,509 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  | (91,436)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember
Level 3 [Member] | Predecessor [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 14,416,488 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 14,019,216 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 14,416,488 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Additions of VIEs consolidated |  |  | (409,300)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |  |
Included in earnings |  |  | 1,057,181 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 721,347 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | (776,014)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 650,373 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues |  |  |  | (162,460)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (716,488)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (439,649)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (1,816,216)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  | 1,598,492 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 1,443,877 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 15,170,359 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 14,416,488 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | (1,053,758)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (587,983)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Level 3 [Member] | Predecessor [Member] | Investments Contract [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 2,261,294 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 2,199,338 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 2,261,294 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | 328,768 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (41,289)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | (89,497)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 103,245 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 2,500,565 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 2,261,294 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | (328,768)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 41,289 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_InvestmentContractsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Level 3 [Member] | Predecessor [Member] | Loans [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 15,359,073 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 14,126,994 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 15,359,073 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | 956,402 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 952,463 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | (849,833)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 637,954 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (713,589)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (358,338)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 14,752,053 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 15,359,073 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | (956,402)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (952,944)ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LoanOriginationCommitmentsMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Level 3 [Member] | Predecessor [Member] | Long-Term Debt [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | (2,956,501)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (1,934,642)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (2,956,501)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Additions of VIEs consolidated |  |  | (409,300)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityAdditionsOfConsolidatedVies / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |  |
Included in earnings |  |  | (138,914)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (208,678)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 150,987 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (98,311)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Issues |  |  |  | (162,460)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityIssues / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | 4,864 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 64,781 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  | 0 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (1,875,121)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  | 1,598,492 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 1,257,930 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | (1,750,372)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (2,956,501)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | 138,914 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 208,678 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByLiabilityClassAxis = us-gaap_LongTermDebtMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Level 3 [Member] | Predecessor [Member] | Investments [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 60,402 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 97,522 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 60,402 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | (33)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (3)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss |  |  | 12,329 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 7,485 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (3,286)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (97,206)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Into Level Three |  |  |  | 58,905 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersIntoLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  |  | (6,301)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 69,412 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 60,402 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_InvestmentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Level 3 [Member] | Predecessor [Member] | Other Assets [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | 14,557 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 16,779 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 14,557 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | (496)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (2,222)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | 14,061 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 14,557 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | 496 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 2,222 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Level 3 [Member] | Predecessor [Member] | Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |
Balance, beginning of period |  |  | (322,337)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (486,775)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (322,337)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Included in earnings |  |  | (88,546)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 21,076 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityGainLossIncludedInEarnings / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements |  |  | (4,477)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (48,886)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilitySettlements / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Transfers Out Of Level Three |  |  |  | 192,248 ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityTransfersOutOfLevelThree / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
Balance, end of period |  |  | (415,360)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (322,337)ambc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date |  |  | $ 92,002 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | $ 113,836 ambc_FairValueAssetOrLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainsLossesStillHeld / us-gaap_FairValueByAssetClassAxis = us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember |

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- Definition The amount of gains or losses included in earnings attributable to unrealized gains or losses on financial instruments measured on a recurring basis using unobservable inputs that are still held at the reporting date. + References No definition available. + Details
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- Definition Fair value measurement with unobservable inputs reconciliation recurring basis asset or liability. + References No definition available. + Details
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- Definition Fair value of financial instruments measured on a recurring basis using unobservable inputs added as a result of new consolidated variable interest entities. + References No definition available. + Details
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- Definition Fair value of financial instruments measured on a recurring basis using unobservable inputs removed as a result of the deconsolidation of variable interest entities. + References No definition available. + Details
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- Definition Amount of gain or loss included in earnings arising from financial instruments measured on a recurring basis using unobservable inputs. + References No definition available. + Details
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- Definition Amount of gain or loss included in other comprehensive income arising from financial instruments measured on a recurring basis using unobservable inputs. + References No definition available. + Details
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- Definition Amount of issuances related to financial instruments measured on a recurring basis using unobservable inputs. + References No definition available. + Details
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- Definition Amount of purchases of financial instruments measured on a recurring basis using unobservable inputs. + References No definition available. + Details
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- Definition Amount of sales of financial instruments measured on a recurring basis using unobservable inputs. + References No definition available. + Details
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- Definition Amount of settlements related to financial instruments measured on a recurring basis using unobservable inputs. + References No definition available. + Details
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- Definition Amount of change in fair value of financial instruments measured on a recurring basis using unobservable inputs arising from transfers into level 3 of the fair value hierarchy. + References No definition available. + Details
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- Definition Amount of change in fair value of financial instruments measured on a recurring basis using unobservable inputs arising from transfers out of level 3 of the fair value hierarchy. + References No definition available. + Details
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