XML 78 R66.htm IDEA: XBRL DOCUMENT v3.5.0.2

Investments - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Investment [Line Items]
Payment of permitted policy claim (percent)					25.00%
Future payment of permitted policy claim (percent)					45.00%
Securities fair value	$ 5,914		$ 5,914		$ 6,762
Fair Value of Securities Placed in Trust	369,127		369,127		396,100
Successor [Member]
Investment [Line Items]
Unrealized losses on securities	13,911		13,911		82,799
Other investments	11,387	$ (1,424)	20,616	$ 10,702
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	52,657		52,657		104,206
Below Investment Grade Securities and Non-Rated Securities [Member] | Successor [Member]
Investment [Line Items]
Fair value of below investment grade securities and non-rated securities	985,810		985,810		953,000
Gross unrealized loss	46,373		46,373		69,214
Ambac Wrapped Securities [Member]
Investment [Line Items]
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	44,680		44,680
Gains (losses) on securities held as of reporting date [Member] | Successor [Member]
Investment [Line Items]
Other investments	8,338	$ (3,482)	11,877	$ (41)
Ambac UK [Member]
Investment [Line Items]
Asset Backed Securities Fair Value Disclosure	$ 120,028		120,028		119,802
National Century Financial Enterprises, Inc. [Member]
Investment [Line Items]
Cash recoveries			$ 0		$ 35

X

- Definition

Asset-backed securities guaranteed by Ambac UK.

+ References

No definition available.

+ Details

Name:	ambc_AssetBackedSecuritiesFairValueDisclosure
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Aggregate losses of below investment grade securities and non rated securities in a continuous unrealized loss position.

+ References

No definition available.

+ Details

Name:	ambc_BelowInvestmentGradeSecuritiesAndNonRatedSecuritiesContinuousUnrealizedLossPositionAggregateLosses
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value of below investment grade securities and non rated securities in a continuous unrealized loss position.

+ References

No definition available.

+ Details

Name:	ambc_BelowInvestmentGradeSecuritiesAndNonRatedSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Percentage of the Segregated Account of Ambac Assurance's permitted policy claims that are to be paid in cash from July 2014 forward as approved by the Rehabilitation Court.

+ References

No definition available.

+ Details

Name:	ambc_CurrentPaymentasaPercentageofPermittedPolicyClaim
Namespace Prefix:	ambc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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

Other Investments Income

+ References

No definition available.

+ Details

Name:	ambc_OtherInvestmentsIncome
Namespace Prefix:	ambc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Percentage of the Segregated Account of Ambac Assurance's permitted policy claims that were paid in cash from September 2012 through June 2014.

+ References

No definition available.

+ Details

Name:	ambc_PaymentAsPercentageOfPermittedPolicyClaim
Namespace Prefix:	ambc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of judgment or settlement awarded to (against) the entity in respect of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_MajorTypesOfDebtAndEquitySecuritiesAxis=ambc_BelowInvestmentGradeSecuritiesAndNonRatedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=ambc_AmbacWrappedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=ambc_GainslossesonsecuritiesheldasofreportingdateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ambc_AmbacUkMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=ambc_NationalCenturyFinancialEnterprisesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: