XML 149 R105.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Investments - Summary of Net Investment Income (Detail) (USD $) In Thousands, unless otherwise specified | 2 Months Ended | 3 Months Ended | 8 Months Ended | 12 Months Ended | 1 Months Ended | 3 Months Ended | 4 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2013 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2013 | Dec. 31, 2013 | Dec. 31, 2014 | Apr. 30, 2013 | Mar. 31, 2013 | Apr. 30, 2013 | Dec. 31, 2012
Successor [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Investment [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Net Realized and Unrealized Gain (Loss) on Trading Securities |  |  |  |  |  |  |  | $ 3,580 us-gaap_NetRealizedOrUnrealizedGainLossOnTradingSecurities / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | $ 6,713 us-gaap_NetRealizedOrUnrealizedGainLossOnTradingSecurities / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Trading Securities, Realized Gain (Loss) |  |  |  |  |  |  |  | 1,702 us-gaap_TradingSecuritiesRealizedGainLoss / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (487)us-gaap_TradingSecuritiesRealizedGainLoss / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Fixed income securities |  |  |  |  |  |  |  | 147,014 ambc_InvestmentIncomeInterestOnDebtSecurities / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 299,694 ambc_InvestmentIncomeInterestOnDebtSecurities / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Short-term investments |  |  |  |  |  |  |  | 1,528 ambc_InvestmentIncomeInsuranceEntityShortTermInvestments / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 3,092 ambc_InvestmentIncomeInsuranceEntityShortTermInvestments / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Loans |  |  |  |  |  |  |  | 306 ambc_InvestmentIncomeInterestOnLoansReceivable / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 529 ambc_InvestmentIncomeInterestOnLoansReceivable / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Investment expense |  |  |  |  |  |  |  | (5,982)us-gaap_InvestmentIncomeInvestmentExpense / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | (10,477)us-gaap_InvestmentIncomeInvestmentExpense / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Securities available-for-sale and short-term |  |  |  |  |  |  |  | 142,866 us-gaap_InterestAndDividendIncomeSecuritiesAvailableForSale / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 292,838 us-gaap_InterestAndDividendIncomeSecuritiesAvailableForSale / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Other investments |  |  |  |  |  |  |  | 3,580 ambc_OtherInvestmentsIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 8,108 ambc_OtherInvestmentsIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Total net investment income | 26,196 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 66,471 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 83,581 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 80,093 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 70,801 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 68,124 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 52,126 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 146,446 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 300,946 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Predecessor [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Investment [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Net Realized and Unrealized Gain (Loss) on Trading Securities |  |  |  |  |  |  |  |  |  |  |  | 369 us-gaap_NetRealizedOrUnrealizedGainLossOnTradingSecurities / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 us-gaap_NetRealizedOrUnrealizedGainLossOnTradingSecurities / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Trading Securities, Realized Gain (Loss) |  |  |  |  |  |  |  |  |  |  |  | 0 us-gaap_TradingSecuritiesRealizedGainLoss / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 us-gaap_TradingSecuritiesRealizedGainLoss / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Fixed income securities |  |  |  |  |  |  |  |  |  |  |  | 118,097 ambc_InvestmentIncomeInterestOnDebtSecurities / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 386,385 ambc_InvestmentIncomeInterestOnDebtSecurities / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Short-term investments |  |  |  |  |  |  |  |  |  |  |  | 677 ambc_InvestmentIncomeInsuranceEntityShortTermInvestments / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 1,405 ambc_InvestmentIncomeInsuranceEntityShortTermInvestments / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Loans |  |  |  |  |  |  |  |  |  |  |  | 146 ambc_InvestmentIncomeInterestOnLoansReceivable / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 714 ambc_InvestmentIncomeInterestOnLoansReceivable / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Investment expense |  |  |  |  |  |  |  |  |  |  |  | (2,549)us-gaap_InvestmentIncomeInvestmentExpense / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | (5,602)us-gaap_InvestmentIncomeInvestmentExpense / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Securities available-for-sale and short-term |  |  |  |  |  |  |  |  |  |  |  | 116,371 us-gaap_InterestAndDividendIncomeSecuritiesAvailableForSale / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 382,902 us-gaap_InterestAndDividendIncomeSecuritiesAvailableForSale / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Other investments |  |  |  |  |  |  |  |  |  |  |  | 369 ambc_OtherInvestmentsIncome / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 0 ambc_OtherInvestmentsIncome / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Total net investment income |  |  |  |  |  |  |  |  |  | 32,226 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 84,514 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 116,740 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | 382,902 us-gaap_NetInvestmentIncome / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember
Gains (losses) on securities held as of reporting date [Member] | Successor [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Investment [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Other investments |  |  |  |  |  |  |  | 1,878 ambc_OtherInvestmentsIncome / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_GainslossesonsecuritiesheldasofreportingdateMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember | 7,200 ambc_OtherInvestmentsIncome / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_GainslossesonsecuritiesheldasofreportingdateMember / us-gaap_StatementScenarioAxis = us-gaap_SuccessorMember |  |  |  |
Gains (losses) on securities held as of reporting date [Member] | Predecessor [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Investment [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Other investments |  |  |  |  |  |  |  |  |  |  |  | $ 369 ambc_OtherInvestmentsIncome / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_GainslossesonsecuritiesheldasofreportingdateMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember | $ 0 ambc_OtherInvestmentsIncome / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = ambc_GainslossesonsecuritiesheldasofreportingdateMember / us-gaap_StatementScenarioAxis = us-gaap_PredecessorMember

X
- Definition Investment Income Insurance Entity Short Term Investments + References No definition available. + Details
Name: | ambc_InvestmentIncomeInsuranceEntityShortTermInvestments
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Investment Income Interest On Debt Securities + References No definition available. + Details
Name: | ambc_InvestmentIncomeInterestOnDebtSecurities
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Investment Income Interest On Loans Receivable + References No definition available. + Details
Name: | ambc_InvestmentIncomeInterestOnLoansReceivable
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Details
Name: | invest_InvestmentLineItems
Namespace Prefix: | invest_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of operating dividend and interest income, including amortization and accretion of premiums and discounts, on available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.2) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 2 -Article 9 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24721-111560 + Details
Name: | us-gaap_InterestAndDividendIncomeSecuritiesAvailableForSale
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of expenses related to the generation of investment income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.2) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.9) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_InvestmentIncomeInvestmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 16 -Article 12 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.2) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 2 -Article 7 + Details
Name: | us-gaap_NetInvestmentIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The sum of the realized and unrealized net gain (loss) on trading securities during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 + Details
Name: | us-gaap_NetRealizedOrUnrealizedGainLossOnTradingSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the gain (loss) realized during the period from the sale of trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Subparagraph c -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
Name: | us-gaap_TradingSecuritiesRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

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

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