Financial Guarantee Insurance Contracts - Summary of Gross Premium Receivable Roll-Forward (Direct and Assumed Contracts) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Insurance [Line Items]
Percentage Premiums Receivable Related To Transactions With Non Investment Grade Internal Ratings	32.00%	32.00%
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Percentage Of Premiums Receivable Related To Non Investment Grade Rmbs Transactions	7.00%	7.00%
Percentage Of Premiums Receivable Related To Student Loan Transactions	7.00%	8.00%
Premiums Receivable, Allowance for Doubtful Accounts	$ 17,082	$ 17,780
Premiums Past Due On Non Investment Grade Obligation	500
Successor [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable	1,000,607		1,453,021
Premium receipts	(27,453)		(33,128)
Adjustments for changes in expected and contractual cash flows	(5,918)		(15,062)
Accretion of premium receivable discount	6,282		10,370
Uncollectable premiums	698		(1,074)
Other adjustments (including foreign exchange)	(22,217)		3,987
Ending premium receivable	$ 951,999		$ 1,418,114

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Percentage of financial guarantee premiums receivable related to RMBS insured transactions with non-investment grade internal ratings.

+ References

No definition available.

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- Definition

Percentage of financial guarantee premiums receivable related to Student Loan insured transactions with non-investment grade internal ratings.

+ References

No definition available.

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- Definition

Percentage of financial guarantee premiums receivable related to insured transactions with non-investment grade internal ratings.

+ References

No definition available.

+ Details

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- Definition

Past due premiums on policies insuring internally rated non-investment grade obligations.

+ References

No definition available.

+ Details

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- Definition

Amount of increase (decrease) in the allowance for doubtful accounts.

+ References

No definition available.

+ Details

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- Definition

Amount of the premium receivable for financial guarantee insurance contracts reported in the statement of financial position. This element primarily would consist of those financial guarantee insurance contracts which premiums are to be collected over the contract period, but may, on occasion, include premiums which are to be collected in full at inception, but which straddle a financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 310

-Section 50

-Paragraph 3

-Subparagraph (c)(1),(5)

-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

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- Definition

Amount of premium payments received during the period for premiums receivable on financial guarantee insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 310

-Section 50

-Paragraph 3

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

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- Definition

This element represents the accretion of the discount for premiums receivable on financial guarantee insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 310

-Section 50

-Paragraph 3

-Subparagraph (c)(4)(iii)

-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

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- Definition

This element represents adjustments to the premium receivable related to financial guarantee insurance contracts due to changes in the period of the contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 310

-Section 50

-Paragraph 3

-Subparagraph (c)(4)(i)

-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

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- Definition

This element represents other adjustments to premiums receivable on financial guarantee insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 310

-Section 50

-Paragraph 3

-Subparagraph (c)(4)(iv)

-URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290

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- Definition

The carrying value as of the balance sheet date of the estimated valuation allowance to reduce gross premiums receivable to net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.5)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 5

-Article 7

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-Subparagraph (SX 210.12-09)

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

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