$AMBC
AMBAC FINANCIAL GROUP INC Stock $ambc

$ambc Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-Q Financial Statement

#000087450119000123 Filed on November 07, 2019

Income Statement

Concept	2019 Q4	2019 Q3	2018 Q3
Revenue	$42.00M	$216.0M	$134.0M
YoY Change	13.51%	61.18%	53.73%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin	$800.0K	$2.300M
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$14.70M	$17.50M	$26.50M
YoY Change	-49.66%	-33.96%	-42.39%
% of Gross Profit
Operating Expenses	$136.4M	$80.20M	$88.30M
YoY Change	1605.0%	-9.17%	-69.51%
Operating Profit
YoY Change
Interest Expense	-$66.70M	-$66.90M	-$65.70M
YoY Change	0.91%	1.83%	125.77%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	-$111.0M	$60.00M	-$39.83M
YoY Change	404.55%	-250.63%	-78.52%
Income Tax	-$1.300M	$3.000M	$2.211M
% Of Pretax Income		5.0%
Net Earnings	-$110.0M	$66.00M	-$104.0M
YoY Change	450.0%	-163.46%	-45.52%
Net Earnings / Revenue	-261.9%	30.56%	-77.6%
Basic Earnings Per Share	-$2.40	$1.44	-$2.27
Diluted Earnings Per Share	-$2.40	$1.41	-$2.27
COMMON SHARES
Basic Shares Outstanding	45.55M shares	46.00M shares	45.75M shares
Diluted Shares Outstanding		47.02M shares	45.75M shares

Balance Sheet

Concept	2019 Q4	2019 Q3	2018 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$24.00M	$52.00M	$52.51M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$25.00M	$26.00M
YoY Change
Goodwill
YoY Change
Intangibles	$427.0M	$433.5M
YoY Change	-40.61%
Long-Term Investments	$46.00M	$44.29M	$38.83M
YoY Change	15.0%	14.05%	15.3%
Other Assets	$57.00M	$16.00M	$1.000M
YoY Change	185.0%	1500.0%	-97.37%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$13.32B	$13.45B	$15.09B
YoY Change	-8.7%	-10.88%	-35.2%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$471.0M	$456.0M	$360.0M
YoY Change	25.27%	26.67%	-14.49%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$471.0M	$456.0M	$391.0M
YoY Change	24.6%	16.62%	-21.01%
LONG-TERM LIABILITIES
Long-Term Debt	$7.376B	$7.308B	$8.524B
YoY Change	-10.03%	-14.27%	-35.51%
Other Long-Term Liabilities	$1.810B	$1.948B	$1.780B
YoY Change	-2.22%	9.44%	-20.75%
Total Long-Term Liabilities	$9.186B	$9.256B	$10.30B
YoY Change	-8.59%	-10.17%	-33.37%
TOTAL LIABILITIES
Total Short-Term Liabilities	$471.0M	$456.0M	$391.0M
Total Long-Term Liabilities	$9.186B	$9.256B	$10.30B
Total Liabilities	$11.78B	$11.82B	$13.34B
YoY Change	-9.05%	-11.35%	-38.78%
SHAREHOLDERS EQUITY
Retained Earnings	$1.203B	$1.313B
YoY Change	-15.34%
Common Stock	$0.00	$456.0K
YoY Change
Preferred Stock
YoY Change
Treasury Stock (at cost)	$0.00	$347.0K
YoY Change
Treasury Stock Shares	16.34K shares	20.48K shares
Shareholders Equity	$1.477B	$1.569B	$1.758B
YoY Change
Total Liabilities & Shareholders Equity	$13.32B	$13.45B	$15.09B
YoY Change	-8.7%	-10.88%	-35.2%

Cashflow Statement

Concept	2019 Q4	2019 Q3	2018 Q3
OPERATING ACTIVITIES
Net Income	-$110.0M	$66.00M	-$104.0M
YoY Change	450.0%	-163.46%	-45.52%
Depreciation, Depletion And Amortization	$14.70M	$17.50M	$26.50M
YoY Change	-49.66%	-33.96%	-42.39%
Cash From Operating Activities	-$14.80M	-$31.30M	-$106.3M
YoY Change	-88.2%	-70.56%	-6.1%
INVESTING ACTIVITIES
Capital Expenditures
YoY Change
Acquisitions
YoY Change
Other Investing Activities	$208.6M	$478.8M	$234.0M
YoY Change	-38.38%	104.62%	300.0%
Cash From Investing Activities	$208.6M	$478.8M	$234.0M
YoY Change	-38.38%	104.62%	300.0%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-180.4M	-425.4M	-119.4M
YoY Change	-1.69%	256.28%	-210.76%
NET CHANGE
Cash From Operating Activities	-14.80M	-31.30M	-106.3M
Cash From Investing Activities	208.6M	478.8M	234.0M
Cash From Financing Activities	-180.4M	-425.4M	-119.4M
Net Change In Cash	13.40M	22.10M	8.300M
YoY Change	-54.73%	166.27%	-84.37%
FREE CASH FLOW
Cash From Operating Activities	-$14.80M	-$31.30M	-$106.3M
Capital Expenditures
Free Cash Flow
YoY Change

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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	ambc	Fair Value Assets Level1to Level2 Transfers Number FairValueAssetsLevel1toLevel2TransfersNumber	0
CY2018Q3	ambc	Fair Value Assets Level2to Level1 Transfers Number FairValueAssetsLevel2toLevel1TransfersNumber	0
CY2019Q3	ambc	Fair Value Assets Level1to Level2 Transfers Number FairValueAssetsLevel1toLevel2TransfersNumber	0
	ambc	Fair Value Assets Level1to Level2 Transfers Number FairValueAssetsLevel1toLevel2TransfersNumber	0
	ambc	Fair Value Assets Level2to Level1 Transfers Number FairValueAssetsLevel2toLevel1TransfersNumber	0
CY2019Q3	ambc	Fair Value Assets Level2to Level1 Transfers Number FairValueAssetsLevel2toLevel1TransfersNumber	0
	ambc	Fair Value Assets Level2to Level1 Transfers Number FairValueAssetsLevel2toLevel1TransfersNumber	0
CY2018Q3	ambc	Fair Value Assets Level2to Level3 Transfers Number FairValueAssetsLevel2toLevel3TransfersNumber	0
	ambc	Fair Value Assets Level2to Level3 Transfers Number FairValueAssetsLevel2toLevel3TransfersNumber	0
CY2019Q3	ambc	Fair Value Assets Level2to Level3 Transfers Number FairValueAssetsLevel2toLevel3TransfersNumber	0
	ambc	Fair Value Assets Level2to Level3 Transfers Number FairValueAssetsLevel2toLevel3TransfersNumber	0
CY2018Q3	ambc	Fair Value Assets Level3to Level2 Transfers Number FairValueAssetsLevel3toLevel2TransfersNumber	0
	ambc	Fair Value Assets Level3to Level2 Transfers Number FairValueAssetsLevel3toLevel2TransfersNumber	0
CY2019Q3	ambc	Fair Value Assets Level3to Level2 Transfers Number FairValueAssetsLevel3toLevel2TransfersNumber	0
	ambc	Fair Value Assets Level3to Level2 Transfers Number FairValueAssetsLevel3toLevel2TransfersNumber	0
	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
	dei	Entity Central Index Key EntityCentralIndexKey	0000874501
CY2018Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2019Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2018Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	130000000	shares
CY2019Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	130000000	shares
CY2018Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	45365170	shares
CY2019Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	45571743	shares
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	45336278	shares
CY2018Q3	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	0	USD
	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	0	USD
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	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	0	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	40000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	82000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	-15000	USD
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CY2018Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
CY2019Q3	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-625000	USD
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	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-6827000	USD
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CY2019Q3	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2018Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2019Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2018Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2019Q3	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2018Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	28892	shares
CY2019Q3	us-gaap	Treasury Stock Shares TreasuryStockShares	20483	shares
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2019-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	1-10777
	dei	Entity Registrant Name EntityRegistrantName	AMBAC FINANCIAL GROUP INC
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	13-3621676
	dei	Entity Address Address Line1 EntityAddressAddressLine1	One State Street Plaza
	dei	Entity Address City Or Town EntityAddressCityOrTown	New York
	dei	Entity Address State Or Province EntityAddressStateOrProvince	NY
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	10004
	dei	City Area Code CityAreaCode	(212)
	dei	Local Phone Number LocalPhoneNumber	658-7470
	dei	Security12b Title Security12bTitle	Common stock par value $0.01 per share
	dei	Trading Symbol TradingSymbol	AMBC
	dei	Security Exchange Name SecurityExchangeName	NASDAQ
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
	dei	Entity Bankruptcy Proceedings Reporting Current EntityBankruptcyProceedingsReportingCurrent	true
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CY2019Q3	us-gaap	Investments Investments	3939121000	USD
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CY2019Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	51951000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	63089000	USD
CY2019Q3	us-gaap	Restricted Cash RestrictedCash	12561000	USD
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CY2019Q3	us-gaap	Premiums Receivable At Carrying Value PremiumsReceivableAtCarryingValue	414744000	USD
CY2018Q4	us-gaap	Premiums Receivable At Carrying Value PremiumsReceivableAtCarryingValue	495391000	USD
CY2019Q3	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	26036000	USD
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	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	-61461000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	51706000	USD
CY2019Q3	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2018Q3	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	3121000	USD
CY2019Q3	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	141376000	USD
	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	81686000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	66116000	USD
CY2018Q3	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	694000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	-103845000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-105514000	USD
	us-gaap	Net Income Loss NetIncomeLoss	206172000	USD
	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	133270000	USD
	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	2676000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	2982000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	66116000	USD
CY2018Q3	us-gaap	Profit Loss ProfitLoss	-22159000	USD
	us-gaap	Profit Loss ProfitLoss	-105514000	USD
CY2019Q3	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	11244000	USD
CY2018Q3	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	1831000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	30459000	USD
CY2019Q3	us-gaap	Revenues Revenues	216162000	USD
CY2018Q3	us-gaap	Revenues Revenues	134015000	USD
	us-gaap	Revenues Revenues	405656000	USD
	us-gaap	Revenues Revenues	458710000	USD
CY2019Q3	us-gaap	Incurred Claims Financial Guarantee Insurance Contracts IncurredClaimsFinancialGuaranteeInsuranceContracts	37139000	USD
CY2018Q3	us-gaap	Incurred Claims Financial Guarantee Insurance Contracts IncurredClaimsFinancialGuaranteeInsuranceContracts	33501000	USD
	us-gaap	Incurred Claims Financial Guarantee Insurance Contracts IncurredClaimsFinancialGuaranteeInsuranceContracts	-83934000	USD
	us-gaap	Incurred Claims Financial Guarantee Insurance Contracts IncurredClaimsFinancialGuaranteeInsuranceContracts	-181315000	USD
CY2019Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	17421000	USD
CY2018Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	26421000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	279941000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	78299000	USD
CY2019Q3	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	25622000	USD
CY2018Q3	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	28368000	USD
	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	79627000	USD
	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	90865000	USD
CY2019Q3	us-gaap	Interest Expense Debt InterestExpenseDebt	66925000	USD
CY2018Q3	us-gaap	Interest Expense Debt InterestExpenseDebt	65673000	USD
	us-gaap	Interest Expense Debt InterestExpenseDebt	202284000	USD
	us-gaap	Interest Expense Debt InterestExpenseDebt	176192000	USD
CY2019Q3	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	147107000	USD
CY2018Q3	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	153963000	USD
	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	477918000	USD
	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	164041000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	69055000	USD
CY2018Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-19948000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-72262000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	294669000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2939000	USD
CY2018Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2211000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	33252000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6811000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	66116000	USD
CY2018Q3	us-gaap	Profit Loss ProfitLoss	-22159000	USD
	us-gaap	Profit Loss ProfitLoss	-105514000	USD
	us-gaap	Profit Loss ProfitLoss	287858000	USD
CY2019Q3	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	0	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	183686000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	31285000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	60807000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	102686000	USD
CY2018Q3	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	81686000	USD
	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	0	USD
CY2018Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	45749252	shares
	us-gaap	Profit Loss ProfitLoss	287858000	USD
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	45939284	shares
CY2019Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-23570000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-8873000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-27532000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-29806000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-74000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	340000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	245000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	548000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	322000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	303000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	277000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	1464000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	7319000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	51971000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	75122000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	152964000	USD
CY2019Q3	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	0	USD
CY2018Q3	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	81686000	USD
	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	0	USD
	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	81686000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	73435000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-51874000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-30392000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	359136000	USD
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.44
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-2.27
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-2.30
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.52
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.41
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-2.27
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-2.30
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.43
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45997694	shares
CY2018Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45749252	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45939284	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45635483	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	47020058	shares
	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	1559039000	USD
	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	-2963000	USD
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46510795	shares
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	73435000	USD
CY2019Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1552916000	USD
CY2019Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2334000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-21000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1628664000	USD
CY2018Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2063921000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	29812000	USD
CY2018Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1710000	USD
CY2018Q3	ambc	Amps Impacton Stockholders Equity AMPSImpactonStockholdersEquity	-296634000	USD
CY2018Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1798809000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1633147000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-30392000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	9699000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-2610000	USD
	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	2000	USD
	ambc	Amps Impacton Stockholders Equity AMPSImpactonStockholdersEquity	18818000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1628664000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1645258000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	440822000	USD
	us-gaap	New Accounting Pronouncement Or Change In Accounting Principle Effect Of Adoption Quantification NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantification	0	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10475000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-1116000	USD
	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	1000	USD
	ambc	Amps Impacton Stockholders Equity AMPSImpactonStockholdersEquity	-296634000	USD
	us-gaap	Proceeds From Warrant Exercises ProceedsFromWarrantExercises	3000	USD
CY2018Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1798809000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-105514000	USD
	us-gaap	Net Income Loss NetIncomeLoss	206172000	USD
	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	0	USD
	ambc	Amps Exchange Loss Basedon Carry Value AMPSExchangeLossBasedonCarryValue	81686000	USD
	us-gaap	Profit Loss ProfitLoss	-105514000	USD
	us-gaap	Profit Loss ProfitLoss	287858000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	356000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	531000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	59291000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	120418000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	9699000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	10475000	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	3292000	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	6121000	USD
	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	27849000	USD
	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-20977000	USD
	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	-118035000	USD
	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	-107114000	USD
	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	460585000	USD
	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	-3570000	USD
	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-81373000	USD
	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-69827000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	64847000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-22935000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	279941000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	78299000	USD
	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	1037000	USD
	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-609000	USD
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	71564000	USD
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	82211000	USD
	us-gaap	Other Than Temporary Impairment Losses Investments Portion In Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent Availableforsale Securities OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAvailableforsaleSecurities	71000	USD
	us-gaap	Other Than Temporary Impairment Losses Investments Portion In Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent Availableforsale Securities OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAvailableforsaleSecurities	1579000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	3121000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	30459000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	2982000	USD
	us-gaap	Increase Decrease In Derivative Assets And Liabilities IncreaseDecreaseInDerivativeAssetsAndLiabilities	-4958000	USD
	us-gaap	Increase Decrease In Derivative Assets And Liabilities IncreaseDecreaseInDerivativeAssetsAndLiabilities	38000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-87415000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-61405000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-296231000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-1417943000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	1051990000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	1091516000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	316818000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	292395000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	866087000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	348682000	USD
	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	72558000	USD
	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	111524000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	134948000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	93800000	USD
	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	235486000	USD
	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	4548000	USD
	us-gaap	Increase Decrease Cash Collateral From Counterparties IncreaseDecreaseCashCollateralFromCounterparties	75018000	USD
	us-gaap	Increase Decrease Cash Collateral From Counterparties IncreaseDecreaseCashCollateralFromCounterparties	10953000	USD
	ambc	Proceeds From Financial Guaranty Variable Interest Entity Assets ProceedsFromFinancialGuarantyVariableInterestEntityAssets	511931000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-2742000	USD
	ambc	Proceeds From Financial Guaranty Variable Interest Entity Assets ProceedsFromFinancialGuarantyVariableInterestEntityAssets	187260000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	360000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	791434000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	1249360000	USD
	ambc	Proceeds From Issuanceof Tier Ii Notes ProceedsFromIssuanceofTierIINotes	0	USD
	ambc	Proceeds From Issuanceof Tier Ii Notes ProceedsFromIssuanceofTierIINotes	240000000	USD
	ambc	Proceeds From Issuanceof Ambac Uk Debt ProceedsFromIssuanceofAmbacUKDebt	12180000	USD
	ambc	Proceeds From Issuanceof Ambac Uk Debt ProceedsFromIssuanceofAmbacUKDebt	0	USD
	ambc	Proceedsfrom Saleof Senior Surplus Notes ProceedsfromSaleofSeniorSurplusNotes	0	USD
	ambc	Proceedsfrom Saleof Senior Surplus Notes ProceedsfromSaleofSeniorSurplusNotes	17714000	USD
	ambc	Paydownof Ambac Note PaydownofAmbacNote	28730000	USD
	ambc	Paydownof Ambac Note PaydownofAmbacNote	185738000	USD
	ambc	Paydown Of Variable Interest Entity Secured Borrowing PaydownOfVariableInterestEntitySecuredBorrowing	0	USD
	ambc	Paydown Of Variable Interest Entity Secured Borrowing PaydownOfVariableInterestEntitySecuredBorrowing	73993000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	191258000	USD
	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	0	USD
	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	9221000	USD
	ambc	Amps Exchange Cash Paid AMPSExchangeCashPaid	0	USD
	ambc	Amps Exchange Cash Paid AMPSExchangeCashPaid	11048000	USD
	ambc	Amps Proceeds AMPSProceeds	18818000	USD
	ambc	Amps Proceeds AMPSProceeds	0	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	2610000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1116000	USD
	us-gaap	Proceeds From Warrant Exercises ProceedsFromWarrantExercises	0	USD
	us-gaap	Proceeds From Warrant Exercises ProceedsFromWarrantExercises	3000	USD
	ambc	Paydownof Financial Guaranty Variable Interest Entity Liabilities PaydownofFinancialGuarantyVariableInterestEntityLiabilities	510228000	USD
	ambc	Paydownof Financial Guaranty Variable Interest Entity Liabilities PaydownofFinancialGuarantyVariableInterestEntityLiabilities	187260000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-510570000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-401917000	USD
	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	-446000	USD
	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	-652000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-15813000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-571152000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	83493000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	624681000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	67680000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	53529000	USD
	dei	Entity Incorporation Date Of Incorporation EntityIncorporationDateOfIncorporation	1991-04-29
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	7319000	USD
CY2019Q3	us-gaap	Minority Interest MinorityInterest	59968000	USD
CY2018Q4	us-gaap	Minority Interest MinorityInterest	41150000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	19368000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-5211000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	11387000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	31408000	USD
CY2018Q3	ambc	Amps Exchange Carrying Valueof Surplus Notes Issued AMPSExchangeCarryingValueofSurplusNotesIssued	187220000	USD
	ambc	Non Cash Exchangeof Puerto Rico Bonds NonCashExchangeofPuertoRicoBonds	510215000	USD
CY2018Q3	ambc	Non Cash Impactof Rehabilitation Exit Transaction NonCashImpactofRehabilitationExitTransaction	1918561000	USD
CY2019Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	51951000	USD
CY2018Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	52505000	USD
CY2019Q3	us-gaap	Restricted Cash RestrictedCash	12561000	USD
CY2018Q3	us-gaap	Restricted Cash RestrictedCash	0	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	67680000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	53529000	USD
	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="line-height:120%;padding-bottom:4px;text-align:justify;font-size:9pt;"><span style="font-family:Times New Roman;font-size:9pt;font-style:normal;font-weight:bold;text-decoration:none;">Reclassifications:</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">Reclassifications have been made to prior years' amounts to conform to the current year's presentation.</span></div>
CY2018Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	15000000	USD
	us-gaap	Description Of New Accounting Pronouncements Not Yet Adopted DescriptionOfNewAccountingPronouncementsNotYetAdopted	<div style="line-height:120%;padding-bottom:4px;font-size:9pt;"><span style="font-family:Times New Roman;font-size:9pt;font-style:normal;font-weight:bold;text-decoration:none;">Future Application of Accounting Standards:</span></div><div style="line-height:120%;padding-bottom:4px;text-align:justify;font-size:9pt;"><span style="font-family:Times New Roman;font-size:9pt;color:#000000;font-style:italic;font-weight:bold;text-decoration:none;">VIE Related Party Guidance</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">In October 2018, the FASB issued ASU 2018-17,</span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;"> Consolidation (Topic 810) - Targeted Improvements to Related Party Guidance for Variable Interest Entities. </span><span style="font-family:inherit;font-size:9pt;color:#000000;">To determine whether a decision-making fee is a variable interest, under the new guidance a reporting entity must consider indirect interests held through related parties under common control on a proportional basis rather than as a direct interest in its entirety (as currently required in GAAP). These amendments create alignment between determining whether a decision making fee is a variable interest and determining whether a reporting entity within a related party group is the primary beneficiary of a VIE. ASU 2018-17 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. Ambac will adopt this ASU on January 1, 2020. The ASU is not expected to have a consequential impact on Ambac's financial statements. </span></div><div style="line-height:120%;padding-bottom:4px;text-align:justify;font-size:9pt;"><span style="font-family:Times New Roman;font-size:9pt;color:#000000;font-style:italic;font-weight:bold;text-decoration:none;">Cloud Computing Arrangement Service Contracts</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">In August 2018, the FASB issued ASU 2018-15,</span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;"> Intangibles—Goodwill and Other— Internal-Use Software (Subtopic 350-40) - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. </span><span style="font-family:inherit;font-size:9pt;color:#000000;">The new guidance requires a customer in a cloud computing arrangement that is a service contract to capitalize certain implementation costs as if the arrangement was an internal-use software project. The internal-use software guidance requires the capitalization of certain costs incurred only during the application development stage. That guidance also requires entities to expense costs during the preliminary project and post-implementation stages as they are incurred. ASU 2018-15 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. The ASU may be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. Ambac will adopt this ASU on January 1, 2020 to prospective costs. The ASU is not expected to have a consequential impact on Ambac's financial statements.</span></div><div style="line-height:120%;padding-bottom:4px;text-align:justify;font-size:9pt;"><span style="font-family:Times New Roman;font-size:9pt;color:#000000;font-style:italic;font-weight:bold;text-decoration:none;">Defined Benefit and Other Postretirement Plans Disclosures</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">In August 2018, the FASB issued ASU 2018-14, </span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;">Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20) - Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans</span><span style="font-family:inherit;font-size:9pt;color:#000000;">. The ASU modifies various disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. Relevant disclosures that will be removed are: i) amounts in accumulated other comprehensive income expected to be recognized as net periodic benefit cost over the next fiscal year and ii) the effects of a one percentage point change in assumed health care cost trend rates on the (a) aggregate of the service and interest cost components of the net periodic pension cost and (b) benefit obligation for postretirement healthcare benefits. Relevant disclosures that will be added are an explanation of the reasons for significant gains and losses related to changes in the benefit obligations for the period. ASU 2018-14 is effective for fiscal years ending after December 15, 2020, with early adoption permitted. The modified disclosures must be applied on a retrospective basis for all periods presented. Ambac will adopt this ASU on December 31, 2020. The ASU is not expected to have a consequential impact on Ambac's financial statements.</span></div><div style="line-height:120%;padding-bottom:4px;text-align:justify;font-size:9pt;"><span style="font-family:Times New Roman;font-size:9pt;color:#000000;font-style:italic;font-weight:bold;text-decoration:none;">Fair Value Measurement Disclosures</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">In August 2018, the FASB issued ASU 2018-13, </span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;">Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement</span><span style="font-family:inherit;font-size:9pt;color:#000000;">. The ASU modifies various disclosure requirements on fair value measurements. Relevant disclosures that will be removed, modified and added are as follows:</span></div><table cellpadding="0" cellspacing="0" style="padding-top:0px;padding-bottom:4px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:9pt;padding-left:12px;"><span style="font-family:inherit;font-size:9pt;">•</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;text-decoration:underline;">Removals</span><span style="font-family:inherit;font-size:9pt;">: 1) Amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, 2) Policy for timing of transfers between levels, and 3) Valuation processes for Level 3 fair value measurements. </span></div></td></tr></table><table cellpadding="0" cellspacing="0" style="padding-top:0px;padding-bottom:4px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:9pt;padding-left:12px;"><span style="font-family:inherit;font-size:9pt;">•</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;text-decoration:underline;">Modifications</span><span style="font-family:inherit;font-size:9pt;">: 1) For investments in certain entities that calculate net asset value, disclosures are only required for the timing of liquidation of an investee's assets and the date when restrictions from redemption might lapse, only if the investee has communicated the timing to the reporting entity or publicly announced it and 2) Clarification that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date and not possible future changes.</span></div></td></tr></table><table cellpadding="0" cellspacing="0" style="padding-bottom:12px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:9pt;padding-left:12px;"><span style="font-family:inherit;font-size:9pt;color:#000000;">•</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;text-decoration:underline;">Additions</span><span style="font-family:inherit;font-size:9pt;color:#000000;">: 1) Changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and 2) Range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Alternatively, an entity may disclose other quantitative information (such as the median or arithmetic average) if it determines that it is a more reasonable and rational method to reflect the distribution of unobservable inputs used.</span></div></td></tr></table><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">ASU 2018-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. Disclosure amendments related to changes in unrealized gains and losses included in other comprehensive income for Level 3 instruments, the range and weighted average of significant unobservable inputs, and the narrative description of measurement uncertainty should be applied prospectively only for </span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">the most recent interim or annual period presented. All other disclosure amendments should be applied retrospectively to all periods presented. Ambac will adopt this ASU on January 1, 2020. The ASU is not expected to have a consequential impact on Ambac's financial statements.</span></div><div style="line-height:120%;padding-bottom:4px;text-align:justify;font-size:9pt;"><span style="font-family:Times New Roman;font-size:9pt;color:#000000;font-style:italic;font-weight:bold;text-decoration:none;">Measurement of Credit Losses on Financial Instruments</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">In June 2016, the FASB issued ASU 2016-13, </span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;">Financial Instruments-Credit Losses (Topic 326) - Measurement of Credit Losses on Financial Instruments, </span><span style="font-family:inherit;font-size:9pt;color:#000000;">subsequently amended by ASU 2018-19</span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;">, Codification Improvements to Topic 326, Financial Instruments - Credit Losses; </span><span style="font-family:inherit;font-size:9pt;color:#000000;">ASU 2019-04</span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;">, </span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;">Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments</span><span style="font-family:inherit;font-size:9pt;color:#000000;">; and ASU 2019-05, </span><span style="font-family:inherit;font-size:9pt;color:#000000;font-style:italic;">Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief </span><span style="font-family:inherit;font-size:9pt;color:#000000;"> (collectively "the ASU").</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">The ASU significantly affects how reporting entities will measure credit losses for financial assets that are not accounted for at fair value through net income, which include loans, debt securities, premium receivables, reinsurance recoverables, net investments in leases, and certain off-balance sheet credit exposures. The ASU does not apply to recoveries of previously paid losses on financial guarantee insurance contracts accounted for under ASC 944. </span></div><table cellpadding="0" cellspacing="0" style="padding-bottom:12px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:48px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:9pt;padding-left:24px;"><span style="font-family:inherit;font-size:9pt;color:#000000;">•</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">For financial assets measured at amortized cost, the ASU replaces the "incurred loss" model, which generally delayed recognition of the full amount of credit losses until the loss was probable of occurring, with an "expected loss" model, which reflects an entity's current estimate of all expected lifetime credit losses. Expected lifetime credit losses for amortized cost assets will be recorded as a valuation allowance, with subsequent increases or decreases in the allowance reflected in the Consolidated Statements of Total Comprehensive Income each period. </span></div></td></tr></table><table cellpadding="0" cellspacing="0" style="padding-bottom:12px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:48px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:9pt;padding-left:24px;"><span style="font-family:inherit;font-size:9pt;color:#000000;">•</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">For available-for-sale debt securities, credit losses under the ASU will be measured similarly to current GAAP. However, under the ASU, credit losses for available-for-sale debt securities will be recorded as a valuation allowance (similar to the amortized cost assets approach described above), rather than as a direct write-down of the security as is required under current GAAP. As a result, improvements to estimated credit losses for available-for-sale debt securities will be recognized immediately in the Consolidated Statements of Total Comprehensive Income rather than as interest income over time. </span></div></td></tr></table><div style="line-height:120%;padding-bottom:12px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">The ASU is effective for annual periods beginning after December 15, 2019, including interim periods within those fiscal years, with early adoption permitted. Ambac will adopt this ASU on January 1, 2020 and continue to evaluate its impact on Ambac's financial statements. We have identified the inventory of financial assets that will be affected by this standard. For assets measured at amortized cost, we are in the process of developing credit loss models, and identifying new data requirements and data sources for implementing those models. For all assets affected by this standard, both amortized cost assets and available-for-sale debt securities, we will evaluate potential changes to accounting processes, including related controls.</span></div>
CY2019Q3	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	2126000	USD
CY2018Q3	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	7000	USD
	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	6493000	USD
	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	1158000	USD
CY2019Q3	ambc	Variable Interest Entities Deconsolidation Gain Loss VariableInterestEntitiesDeconsolidationGainLoss	-1998000	USD
CY2018Q3	ambc	Variable Interest Entities Deconsolidation Gain Loss VariableInterestEntitiesDeconsolidationGainLoss	1824000	USD
	ambc	Variable Interest Entities Deconsolidation Gain Loss VariableInterestEntitiesDeconsolidationGainLoss	-1998000	USD
	ambc	Variable Interest Entities Deconsolidation Gain Loss VariableInterestEntitiesDeconsolidationGainLoss	1824000	USD
CY2019Q3	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	0	USD
CY2018Q3	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	0	USD
	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	14864000	USD
	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	0	USD
CY2019Q3	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	11244000	USD
CY2018Q3	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	1831000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	30459000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	2982000	USD
	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	14864000	USD
CY2019Q3	us-gaap	Variable Interest Entity Consolidated Carrying Amount Assets VariableInterestEntityConsolidatedCarryingAmountAssets	292003000	USD
CY2019Q3	us-gaap	Variable Interest Entity Consolidated Carrying Amount Liabilities VariableInterestEntityConsolidatedCarryingAmountLiabilities	363628000	USD
CY2019Q3	ambc	Deconsolidated Vie Assets DeconsolidatedVIEAssets	1233132000	USD
CY2019Q3	ambc	Deconsolidated Vie Liabilities DeconsolidatedVIELiabilities	1230473000	USD
CY2019Q3	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	31500963000	USD
CY2019Q3	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Assets VariableInterestEntityNonconsolidatedCarryingAmountInsuranceAssets	2295032000	USD
CY2019Q3	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Liabilities VariableInterestEntityNonconsolidatedCarryingAmountInsuranceLiabilities	1103793000	USD
CY2019Q3	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Derivative Net Assets Or Liabilities VariableInterestEntityNonconsolidatedCarryingAmountDerivativeNetAssetsOrLiabilities	7512000	USD
CY2018Q4	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	35566155000	USD
CY2018Q4	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Assets VariableInterestEntityNonconsolidatedCarryingAmountInsuranceAssets	2257824000	USD
CY2018Q4	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Liabilities VariableInterestEntityNonconsolidatedCarryingAmountInsuranceLiabilities	1433877000	USD
CY2019Q3	us-gaap	Equity Method Investments Fair Value Disclosure EquityMethodInvestmentsFairValueDisclosure	3388000	USD
CY2018Q4	us-gaap	Equity Method Investments Fair Value Disclosure EquityMethodInvestmentsFairValueDisclosure	4516000	USD
CY2019Q3	us-gaap	Equity Method Investments EquityMethodInvestments	44287000	USD
CY2018Q4	us-gaap	Equity Method Investments EquityMethodInvestments	40168000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	19088000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	26144000	USD
CY2019Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	18825000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26407000	USD
CY2018Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	45854000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	81869000	USD
CY2018Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	29898000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	51971000	USD
CY2018Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	97825000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-48715000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	147336000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	72214000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	75122000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26407000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-52239000	USD
CY2017Q4	us-gaap	New Accounting Pronouncement Or Change In Accounting Principle Cumulative Effect Of Change On Equity Or Net Assets1 NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1	-2900000	USD
CY2017Q4	ambc	Accumulated Other Comprehensive Income Loss Restated AccumulatedOtherComprehensiveIncomeLossRestated	-55139000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	233956000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	80992000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	152964000	USD
CY2018Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	97825000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	245000	USD
CY2019Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	45551260	shares
CY2013Q2	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2019Q3	us-gaap	Class Of Warrant Or Right Outstanding ClassOfWarrantOrRightOutstanding	4877783	shares
CY2013Q2	us-gaap	Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1 ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1	16.67
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45997694	shares
CY2018Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45749252	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45939284	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45635483	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	47020058	shares
CY2018Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	45749252	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	45939284	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46510795	shares
CY2019Q3	ambc	Estimated Future Premium Payments Weighted Average Discounted Rate EstimatedFuturePremiumPaymentsWeightedAverageDiscountedRate	0.024
CY2018Q4	ambc	Estimated Future Premium Payments Weighted Average Discounted Rate EstimatedFuturePremiumPaymentsWeightedAverageDiscountedRate	0.027
	us-gaap	Financial Guarantee Insurance Contracts Premium Received Over Contract Period Premium Receivable Weighted Average Collection Period1 FinancialGuaranteeInsuranceContractsPremiumReceivedOverContractPeriodPremiumReceivableWeightedAverageCollectionPeriod1	P8Y7M6D
CY2018Q4	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	7136000	USD
CY2019Q3	ambc	Premiums Past Due On Non Investment Grade Obligations PremiumsPastDueOnNonInvestmentGradeObligations	100000	USD
CY2018	us-gaap	Financial Guarantee Insurance Contracts Premium Received Over Contract Period Premium Receivable Weighted Average Collection Period1 FinancialGuaranteeInsuranceContractsPremiumReceivedOverContractPeriodPremiumReceivableWeightedAverageCollectionPeriod1	P8Y8M12D
CY2019Q3	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	13943000	USD
CY2018Q4	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	495391000	USD
CY2017Q4	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	586312000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable Proceeds From Premiums Received FinancialGuaranteeInsuranceContractsPremiumReceivableProceedsFromPremiumsReceived	-36778000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable Proceeds From Premiums Received FinancialGuaranteeInsuranceContractsPremiumReceivableProceedsFromPremiumsReceived	-42660000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Change In Period Of Contract FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentChangeInPeriodOfContract	-32593000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Change In Period Of Contract FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentChangeInPeriodOfContract	-34088000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Accretion Of Discount On Premium Receivable FinancialGuaranteeInsuranceContractsPremiumsReceivableAccretionOfDiscountOnPremiumReceivable	8775000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Accretion Of Discount On Premium Receivable FinancialGuaranteeInsuranceContractsPremiumsReceivableAccretionOfDiscountOnPremiumReceivable	11211000	USD
	ambc	Financial Guarantee Insurance Contracts Premium Receivable Deconsolidationof Vie FinancialGuaranteeInsuranceContractsPremiumReceivableDeconsolidationofVIE	3239000	USD
	us-gaap	Allowance For Doubtful Accounts Receivable Period Increase Decrease AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease	-6921000	USD
	us-gaap	Allowance For Doubtful Accounts Receivable Period Increase Decrease AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease	2473000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Other Adjustments FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentOtherAdjustments	-16369000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Other Adjustments FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentOtherAdjustments	-6051000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	414744000	USD
CY2018Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	517197000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	2019000	USD
	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	8073000	USD
CY2018Q3	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	6751000	USD
	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	22246000	USD
CY2019Q3	us-gaap	Direct Premiums Written DirectPremiumsWritten	-13480000	USD
CY2019Q3	us-gaap	Direct Premiums Earned DirectPremiumsEarned	13097000	USD
CY2018Q3	us-gaap	Direct Premiums Written DirectPremiumsWritten	-22954000	USD
CY2018Q3	us-gaap	Direct Premiums Earned DirectPremiumsEarned	27559000	USD
CY2019Q3	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
CY2019Q3	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	19000	USD
CY2018Q3	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
CY2018Q3	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	20000	USD
CY2019Q3	us-gaap	Ceded Premiums Written CededPremiumsWritten	22873000	USD
CY2019Q3	us-gaap	Ceded Premiums Earned CededPremiumsEarned	2650000	USD
CY2018Q3	us-gaap	Ceded Premiums Written CededPremiumsWritten	-789000	USD
CY2018Q3	us-gaap	Ceded Premiums Earned CededPremiumsEarned	1939000	USD
CY2019Q3	us-gaap	Premiums Written Net PremiumsWrittenNet	-36353000	USD
CY2019Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	10466000	USD
CY2018Q3	us-gaap	Premiums Written Net PremiumsWrittenNet	-22165000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Five And Within10 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanFiveAndWithin10YearsFromBalanceSheetDate	135566000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than10 And Within15 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan10AndWithin15YearsFromBalanceSheetDate	90347000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than10 And Within15 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan10AndWithin15YearsFromBalanceSheetDate	108291000	USD
CY2018Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	25640000	USD
	us-gaap	Direct Premiums Written DirectPremiumsWritten	-30739000	USD
	us-gaap	Direct Premiums Earned DirectPremiumsEarned	52596000	USD
	us-gaap	Direct Premiums Written DirectPremiumsWritten	-19304000	USD
	us-gaap	Direct Premiums Earned DirectPremiumsEarned	87506000	USD
	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	59000	USD
	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	59000	USD
	us-gaap	Ceded Premiums Written CededPremiumsWritten	22030000	USD
	us-gaap	Ceded Premiums Earned CededPremiumsEarned	6598000	USD
	us-gaap	Ceded Premiums Written CededPremiumsWritten	-1832000	USD
	us-gaap	Ceded Premiums Earned CededPremiumsEarned	5206000	USD
	us-gaap	Premiums Written Net PremiumsWrittenNet	-52769000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	46057000	USD
	us-gaap	Premiums Written Net PremiumsWrittenNet	-17472000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	82359000	USD
CY2019Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	10466000	USD
CY2018Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	25640000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	46057000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	82359000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected During Fourth Quarter Following Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedDuringFourthQuarterFollowingBalanceSheetDate	11888000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized During Fourth Quarter Following Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedDuringFourthQuarterFollowingBalanceSheetDate	10507000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than One And Within Two Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanOneAndWithinTwoYearsFromBalanceSheetDate	41442000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than One And Within Two Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanOneAndWithinTwoYearsFromBalanceSheetDate	40407000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Two And Within Three Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanTwoAndWithinThreeYearsFromBalanceSheetDate	35601000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Two And Within Three Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanTwoAndWithinThreeYearsFromBalanceSheetDate	36938000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Three And Within Four Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanThreeAndWithinFourYearsFromBalanceSheetDate	35292000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Three And Within Four Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanThreeAndWithinFourYearsFromBalanceSheetDate	34531000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Four And Within Five Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanFourAndWithinFiveYearsFromBalanceSheetDate	33792000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Four And Within Five Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanFourAndWithinFiveYearsFromBalanceSheetDate	32345000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Five And Within10 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanFiveAndWithin10YearsFromBalanceSheetDate	147828000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than20 And Within25 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan20AndWithin25YearsFromBalanceSheetDate	24772000	USD
CY2019Q3	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	-513554000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than15 And Within20 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan15AndWithin20YearsFromBalanceSheetDate	57282000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than15 And Within20 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan15AndWithin20YearsFromBalanceSheetDate	46459000	USD
CY2018Q3	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	-55453000	USD
CY2019Q3	ambc	Impactof Vie Consolidationon Gross Lossand Loss Reserves ImpactofVIEConsolidationonGrossLossandLossReserves	72159000	USD
CY2019Q3	ambc	Loss Reserves Ceded To Reinsurers LossReservesCededToReinsurers	25749000	USD
CY2018Q3	ambc	Loss Reserves Ceded To Reinsurers LossReservesCededToReinsurers	25326000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than20 And Within25 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan20AndWithin25YearsFromBalanceSheetDate	16205000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than25 And Within30 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan25AndWithin30YearsFromBalanceSheetDate	11298000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than25 And Within30 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan25AndWithin30YearsFromBalanceSheetDate	6637000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than30 And Within35 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan30AndWithin35YearsFromBalanceSheetDate	2251000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than30 And Within35 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan30AndWithin35YearsFromBalanceSheetDate	1314000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than35 And Within40 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan35AndWithin40YearsFromBalanceSheetDate	31000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than35 And Within40 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan35AndWithin40YearsFromBalanceSheetDate	20000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable Premium Expected To Be Collected FinancialGuaranteeInsuranceContractsPremiumReceivablePremiumExpectedToBeCollected	509768000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognized	451276000	USD
CY2019Q3	us-gaap	Liability Net For Claims And Claims Adjustment Expense Financial Guarantee Insurance Contracts LiabilityNetForClaimsAndClaimsAdjustmentExpenseFinancialGuaranteeInsuranceContracts	1522304000	USD
CY2019Q3	us-gaap	Salvage And Subrogation Recoveries Value SalvageAndSubrogationRecoveriesValue	2082268000	USD
CY2019Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionClaimLiability	-559964000	USD
CY2018Q4	us-gaap	Liability Net For Claims And Claims Adjustment Expense Financial Guarantee Insurance Contracts LiabilityNetForClaimsAndClaimsAdjustmentExpenseFinancialGuaranteeInsuranceContracts	1826078000	USD
CY2018Q4	us-gaap	Salvage And Subrogation Recoveries Value SalvageAndSubrogationRecoveriesValue	1932960000	USD
CY2018Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionClaimLiability	-106882000	USD
	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	<div style="line-height:120%;padding-bottom:4px;text-align:justify;padding-left:0px;text-indent:0px;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;color:#000000;">Below is the loss and loss expense reserve roll-forward, net of subrogation recoverable and reinsurance, for the affected periods:</span></div><div style="line-height:120%;padding-bottom:4px;padding-top:0px;text-align:justify;font-size:10pt;"><div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;width:99.79035639412997%;border-collapse:collapse;text-align:left;"><tr><td colspan="8"/></tr><tr><td style="width:60%;"/><td style="width:1%;"/><td style="width:17%;"/><td style="width:1%;"/><td style="width:2%;"/><td style="width:1%;"/><td style="width:17%;"/><td style="width:1%;"/></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="7" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:center;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">Nine Months Ended September 30,</span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:center;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">2019</span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:center;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">2018</span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">Beginning gross loss and loss expense reserves</span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">$</span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(106,882</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">$</span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;"><span>4,113,802</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Reinsurance recoverable</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>22,623</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>40,658</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Beginning balance of net loss and loss expense reserves</span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(129,505</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>4,073,144</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">Losses and loss expenses (benefit):</span></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Current year</span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>659</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>976</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;padding-left:6px;text-indent:-6px;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Prior years</span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(84,593</span></span></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>(182,291</span></span></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">)</span></div></td></tr><tr><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="text-align:left;padding-left:6px;text-indent:-6px;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Total </span><span style="font-family:inherit;font-size:8pt;"><sup style="vertical-align:top;line-height:120%;font-size:5pt">(1) (2) (3)</sup></span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(83,934</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>(181,315</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">)</span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;padding-left:6px;text-indent:-6px;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">Loss and loss expenses paid (recovered):</span></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Current year</span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>32</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>143</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Prior years </span><span style="font-family:inherit;font-size:8pt;"><sup style="vertical-align:top;line-height:120%;font-size:5pt">(3)</sup></span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>298,909</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>3,937,561</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="text-align:left;padding-left:6px;text-indent:-6px;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Total</span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>298,941</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>3,937,704</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="text-align:left;padding-left:6px;text-indent:-6px;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Foreign exchange effect</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(1,174</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>(9,578</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">)</span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;padding-left:6px;text-indent:-6px;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Ending net loss and loss expense reserves </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(513,554</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>(55,453</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">)</span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Impact of VIE consolidation</span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(72,159</span></span></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">—</span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">Reinsurance recoverable </span><span style="font-family:inherit;font-size:8pt;"><sup style="vertical-align:top;line-height:120%;font-size:5pt">(4)</sup></span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>25,749</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;"><span>25,326</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">Ending gross loss and loss expense reserves</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">$</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;"><span>(559,964</span></span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;color:#2a1aff;font-weight:bold;">)</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">$</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;"><span>(30,127</span></span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;font-weight:bold;">)</span></div></td></tr></table></div><span style="font-family:Times New Roman;font-size:8pt;"><br/></span></div><table cellpadding="0" cellspacing="0" style="padding-top:0px;padding-bottom:4px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:8pt;padding-left:0px;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">(1)</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:8pt;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">Total losses and loss expenses (benefit) includes </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$(5,999)</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> and </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$(123)</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> for the </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">nine months ended September 30, 2019 and 2018</span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">, respectively, related to ceded reinsurance.</span></div></td></tr></table><table cellpadding="0" cellspacing="0" style="padding-top:0px;padding-bottom:4px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:8pt;padding-left:0px;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">(2)</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:8pt;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">Ambac records the impact of estimated recoveries related to securitized loans in RMBS transactions that breached certain representations and warranties ("R&W"s) by transaction sponsors within losses and loss expenses (benefit). The losses and loss expense (benefit) incurred associated with changes in estimated R&Ws for the </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">nine months ended September 30, 2019 and 2018</span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> was </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$15,365</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> and </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$56,928</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">, respectively.</span></div></td></tr></table><table cellpadding="0" cellspacing="0" style="padding-top:0px;padding-bottom:4px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;font-size:8pt;padding-left:0px;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">(3)</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;text-align:justify;font-size:8pt;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">On February 12, 2018, Deferred Amounts and Interest Accrued on Deferred Amounts in the amount of </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$3,000,158</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> and </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$856,834</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">, respectively were settled in connection with the Rehabilitation Exit Transactions. 2018 includes a </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$288,204</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> loss and loss expense benefit on these settled Deferred Amounts.</span></div></td></tr></table><div style="line-height:120%;font-size:8pt;padding-left:0px;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">(4)</span></div><div style="line-height:120%;text-align:justify;font-size:8pt;"><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">Represents reinsurance recoverable on future loss and loss expenses. Additionally, the Balance Sheet line "Reinsurance recoverable on paid and unpaid losses" includes reinsurance recoverables (payables) of </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$287</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> and </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"><span>$185</span></span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;"> as of </span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">September 30, 2019 and 2018</span><span style="font-family:Times New Roman;font-size:8pt;color:#000000;">, respectively, related to previously presented loss and loss expenses and subrogation.</span></div>
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CY2019Q3	us-gaap	Fair Value Liabilities Measured On Recurring Basis Change In Unrealized Gain Loss FairValueLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2018Q3	us-gaap	Fair Value Liabilities Measured On Recurring Basis Change In Unrealized Gain Loss FairValueLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2018Q4	ambc	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability	72071000	USD
CY2017Q4	ambc	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability	808557000	USD
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CY2019Q3	ambc	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability	79421000	USD
CY2018Q3	ambc	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiability	72094000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3310649000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	167394000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	1349000	USD
CY2019Q3	us-gaap	Available For Sale Securities Current AvailableForSaleSecuritiesCurrent	3476694000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Other Than Temporary Impairment Not Credit Loss Net Of Tax Availableforsale Debt Securities AccumulatedOtherComprehensiveIncomeLossOtherThanTemporaryImpairmentNotCreditLossNetOfTaxAvailableforsaleDebtSecurities	58000	USD
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CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	133052000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	38195000	USD
CY2018Q4	us-gaap	Available For Sale Securities Current AvailableForSaleSecuritiesCurrent	3546006000	USD
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CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	769767000	USD
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CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	1221570000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	443917000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	471856000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	225990000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	259122000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	2642057000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	2722315000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3310649000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3476694000	USD
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CY2019Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	981000	USD
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CY2018Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	38195000	USD
CY2013Q2	us-gaap	Fresh Start Balance Sheet Fresh Start Balance Sheet Dates FreshStartBalanceSheetFreshStartBalanceSheetDates	2013-04-30
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CY2018Q3	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	30909000	USD
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CY2019Q3	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	365000	USD
CY2018Q3	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	2171000	USD
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CY2018Q4	ambc	Fair Value Of Securities Deposited With Governmental Authorities FairValueOfSecuritiesDepositedWithGovernmentalAuthorities	5975000	USD
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CY2018Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	67071000	USD
CY2019Q3	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	120733000	USD
CY2018Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	83700000	USD
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CY2019Q3	us-gaap	Variable Lease Cost VariableLeaseCost	50000	USD
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CY2019Q3	us-gaap	Lease Cost LeaseCost	1977000	USD
	us-gaap	Lease Cost LeaseCost	5547000	USD
CY2019Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	1641000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	4927000	USD
CY2019Q3	ambc	Rightof Use Assets Obtainedin Exchangefor Lease Obligation Non Cash RightofUseAssetsObtainedinExchangeforLeaseObligationNonCash	588000	USD
	ambc	Rightof Use Assets Obtainedin Exchangefor Lease Obligation Non Cash RightofUseAssetsObtainedinExchangeforLeaseObligationNonCash	29887000	USD
CY2018Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	14360	USD
CY2019Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	25906000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	29600000	USD
CY2019Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P10Y
CY2019Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.078
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	1108000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	4138000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	4014000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	4014000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	4014000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	26147000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	43435000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	-13835000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	29600000	USD
CY2019Q2	us-gaap	Lessor Operating Lease Term Of Contract LessorOperatingLeaseTermOfContract	P10Y3M18D
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Receivable Remainder Of Fiscal Year OperatingLeasesFutureMinimumPaymentsReceivableRemainderOfFiscalYear	172000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Receivable In Two Years OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears	1038000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Receivable In Three Years OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears	1051000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Receivable In Four Years OperatingLeasesFutureMinimumPaymentsReceivableInFourYears	1078000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Receivable In Five Years OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears	1131000	USD
CY2019Q3	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	7571000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	12041000	USD
	ambc	General Obligation Bonds Issuedin2012and2014 GeneralObligationBondsIssuedin2012and2014	6000000000	USD
CY2019Q3	us-gaap	Former Gain Contingency Recognized In Current Period FormerGainContingencyRecognizedInCurrentPeriod	142225000	USD

Files In Submission

Name	View Source	Status
0000874501-19-000123-index-headers.html	Edgar Link	pending
0000874501-19-000123-index.html	Edgar Link	pending
0000874501-19-000123.txt	Edgar Link	pending
0000874501-19-000123-xbrl.zip	Edgar Link	pending
a02-019ambcex311x3q191.htm	Edgar Link	pending
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a02-019ambcex32x1x3q19.htm	Edgar Link	pending
a02-019ambcx20190930x1.htm	Edgar Link	pending
a02-019ambcx20190930x1_htm.xml	Edgar Link	completed
ambc-20190930.xsd	Edgar Link	pending
ambc-20190930_cal.xml	Edgar Link	unprocessable
ambc-20190930_def.xml	Edgar Link	unprocessable
ambc-20190930_lab.xml	Edgar Link	unprocessable
ambc-20190930_pre.xml	Edgar Link	unprocessable
chart-56ba7b50fd7d59ae974.jpg	Edgar Link	pending
chart-b97729d4d49b51c2b8d.jpg	Edgar Link	pending
chart-f42d11d8faaa520eba8.jpg	Edgar Link	pending
chart-f432d9e150bd5d9686b.jpg	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
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$AMBC
AMBAC FINANCIAL GROUP INC Stock $ambc

2019 Q4 Form 10-Q Financial Statement

#000087450119000123 Filed on November 07, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AMBC AMBAC FINANCIAL GROUP INC Stock $ambc

2019 Q4 Form 10-Q Financial Statement

#000087450119000123 Filed on November 07, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AMBC
AMBAC FINANCIAL GROUP INC Stock $ambc