Derivative Instruments - Summarize Information by Major Category of CDS Contracts (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015 Transactions	Dec. 31, 2014 Transactions
Summary of information by major category of CDS contracts
Gross principal notional outstanding	1,594,571invest_DerivativeNotionalAmount	1,529,759invest_DerivativeNotionalAmount
Successor [Member]
Summary of information by major category of CDS contracts
Number of CDS transactions	15	16
Remaining expected weighted-average life of obligations (in years)	4 years 4 months 20 days	4 years 1 month 12 days
CLO [Member] \| Successor [Member]
Summary of information by major category of CDS contracts
Number of CDS transactions	5	6
Remaining expected weighted-average life of obligations (in years)	1 year 6 months 1 day	1 year 9 months 18 days
Gross principal notional outstanding	466,453	549,923
CLO [Member] \| Successor [Member] \| Credit Derivatives [Member]
Summary of information by major category of CDS contracts
Net derivative liabilities at fair value	1,533	2,027
Other [Member] \| Successor [Member]
Summary of information by major category of CDS contracts
Number of CDS transactions	10	10
Remaining expected weighted-average life of obligations (in years)	5 years 7 months 1 day	5 years 5 months 2 days
Gross principal notional outstanding	1,128,118	979,836
Other [Member] \| Successor [Member] \| Credit Derivatives [Member]
Summary of information by major category of CDS contracts
Net derivative liabilities at fair value	74,844	71,432

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Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226008-175313

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226006-175313

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41678-113959

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- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5580258-113959

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579245-113959

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