XML 120 R98.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Derivative Instruments - Summary of Gross Principal Notional Outstanding for CDS Contracts (Detail) - Other Derivatives [Member] - Successor [Member] - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Ambac Rating |  |
Notional outstanding | $ 325,890 | $ 737,380
AAA Rating [Member] |  |
Ambac Rating |  |
Notional outstanding | 0 | 0
AA Rating [Member] |  |
Ambac Rating |  |
Notional outstanding | 175,765 | 315,201
A Rating [Member] |  |
Ambac Rating |  |
Notional outstanding | 0 | 227,146
BBB Rating [Member] |  |
Ambac Rating |  |
Notional outstanding | 150,125 | 127,250
Below Investment Grade Rating [Member] |  |
Ambac Rating |  |
Notional outstanding | $ 0 | $ 67,783

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_NotionalAmountOfDerivativesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_CreditDerivativesByContractTypeAxis=us-gaap_OtherCreditDerivativesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | invest_CreditRatingSourceAxis=ambc_AaaRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_CreditRatingSourceAxis=ambc_AaRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_CreditRatingSourceAxis=ambc_RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_CreditRatingSourceAxis=ambc_BbbRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_CreditRatingSourceAxis=ambc_BelowInvestmentGradeRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |