XML 128 R108.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Income Taxes Income Taxes - NOL Usage Table (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended | 36 Months Ended | 48 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2018 | Sep. 30, 2011 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2016
Net Income Loss Reconciliation [Line Items] |  |  |  |  |  |  |  |
TierABCCredit | $ 5,000 |  |  |  | $ 5,000 |  |  |
TierABCredit |  |  |  | $ (10,000) |  |  |  |
NOL allocated amount |  | $ 3,650,000 | $ 3,423,704 |  |  |  | $ 3,423,704 |
Tolling Payment to AFG |  |  |  |  | $ 71,454 |  |  | $ 100,145
Tolling Payment Payable to AFG |  |  | 44,381 | $ 30,496 |  | $ 30,496 | 44,381 |
Tolling Payment Payable to AFG |  |  | $ 13,885 |  |  |  | $ 13,885 | $ 28,691
Tier C Tolling Payment Payable to IRS |  |  | 12.50% |  |  |  | 12.50% |
Tier D Tolling Payments Payable to IRS |  |  | 17.50% |  |  |  | 17.50% |
Ambac Assurance [Member] |  |  |  |  |  |  |  |
Net Income Loss Reconciliation [Line Items] |  |  |  |  |  |  |  |
AACNetTaxableIncome |  |  |  |  |  | 1,486,879 |  |
NOL allocated amount |  |  | $ 2,163,121 |  |  |  | $ 2,163,121 |
AACNetTaxableIncomeFromTierB |  |  |  |  |  | $ 1,007,879 | 1,007,879 |
Percentage Of Notional Federal Tax Liability |  | 25.00% |  |  |  |  |  |
AFG [Member] |  |  |  |  |  |  |  |
Net Income Loss Reconciliation [Line Items] |  |  |  |  |  |  |  |
NOL allocated amount |  |  | 1,260,583 |  |  |  | 1,260,583 |
Tier A [Member] |  |  |  |  |  |  |  |
Net Income Loss Reconciliation [Line Items] |  |  |  |  |  |  |  |
NOL allocated amount |  | $ 479,000 | $ 479,000 |  |  |  | 479,000 |
NOL applicable percentage |  |  | 15.00% |  |  |  |  |
Tier B [Member] |  |  |  |  |  |  |  |
Net Income Loss Reconciliation [Line Items] |  |  |  |  |  |  |  |
NOL allocated amount |  | $ 1,057,000 | $ 1,057,000 |  |  |  | 1,057,000 |
NOL applicable percentage |  |  | 40.00% |  |  |  |  |
Tier C [Member] |  |  |  |  |  |  |  |
Net Income Loss Reconciliation [Line Items] |  |  |  |  |  |  |  |
NOL allocated amount |  |  | $ 1,057,000 |  |  |  | 1,057,000 |
NOL applicable percentage |  |  | 10.00% |  |  |  |  |
Tier D [Member] |  |  |  |  |  |  |  |
Net Income Loss Reconciliation [Line Items] |  |  |  |  |  |  |  |
NOL allocated amount |  |  | $ 1,057,000 |  |  |  | $ 1,057,000 |
NOL applicable percentage |  |  | 15.00% |  |  |  |  |

X
- Definition AACNetTaxableIncome + References No definition available. + Details
Name: | ambc_AACNetTaxableIncome
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition AACNetTaxableIncomeFromTierB + References No definition available. + Details
Name: | ambc_AACNetTaxableIncomeFromTierB
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Net Income Loss Reconciliation [Line Items] + References No definition available. + Details
Name: | ambc_NetIncomeLossReconciliationLineItems
Namespace Prefix: | ambc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net Operating Loss Percentage + References No definition available. + Details
Name: | ambc_NetOperatingLossPercentage
Namespace Prefix: | ambc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Notional Federal Tax Liability + References No definition available. + Details
Name: | ambc_PercentageOfNotionalFederalTaxLiability
Namespace Prefix: | ambc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition TierABCCredit + References No definition available. + Details
Name: | ambc_TierABCCredit
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition TierABCredit + References No definition available. + Details
Name: | ambc_TierABCredit
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Tier C Tolling Payments Payable to IRS + References No definition available. + Details
Name: | ambc_TierCTollingPaymentsPayabletoIRS
Namespace Prefix: | ambc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier D Tolling Payments Payable to IRS + References No definition available. + Details
Name: | ambc_TierDTollingPaymentsPayabletoIRS
Namespace Prefix: | ambc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tolling Payment Payable to AFG + References No definition available. + Details
Name: | ambc_TollingPaymentPayabletoAFG
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tolling Payment Payable to AFG, Gross + References No definition available. + Details
Name: | ambc_TollingPaymentPayabletoAFGGross
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tolling Payment to AFG + References No definition available. + Details
Name: | ambc_TollingPaymenttoAFG
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319 + Details
Name: | us-gaap_OperatingLossCarryforwards
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=ambc_AmbacAssuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ambc_AfgMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxCreditCarryforwardAxis=ambc_TierAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxCreditCarryforwardAxis=ambc_TierBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxCreditCarryforwardAxis=ambc_TierCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxCreditCarryforwardAxis=ambc_TierDMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |