XML 87 R72.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Investments - Summary of Sources of Collateral Received and Various Investment Agreement in which Collateral Pledged (Detail) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Investment [Line Items] |  |
Fair Value Of Securities Deposited With Governmental Authorities | $ 5,912 | $ 5,974
Fair Value of Securities Placed in Trust | 0 | 346,212
Market Value of Secured Note Collateral | 255,628 |
Successor [Member] | Cash and Securities Pledged Directly from Investment Portfolio [Member] |  |
Investment [Line Items] |  |
Fair Value of Cash and Securities Pledged to Derivative Counterparties | $ 105,701 | $ 120,645

X
- Definition Fair value of cash and securities pledged to derivative counterparties. + References No definition available. + Details
Name: | ambc_FairValueOfCashAndSecuritiesPledgedToDerivativeCounterparties
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of securities deposited with governmental authorities. + References No definition available. + Details
Name: | ambc_FairValueOfSecuritiesDepositedWithGovernmentalAuthorities
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair Value of Securities Placed in Trust + References No definition available. + Details
Name: | ambc_FairValueofSecuritiesPlacedinTrust
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Market Value of Secured Note Collateral + References No definition available. + Details
Name: | ambc_MarketValueofSecuredNoteCollateral
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent reporting concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 12 -Sentence Column A + Details
Name: | invest_InvestmentLineItems
Namespace Prefix: | invest_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_SuccessorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=ambc_InvestmentPortfolioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |