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Fair Value Measurements - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
	Apr. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit valuation adjustment included in fair value of credit derivative liabilities		$ 38,966	$ 261,203
Credit valuation adjustment included in fair value of derivative liabilities other than credit derivatives		48,425	121,928
Percentage of CDS gross par outstanding used in the determination of CDS fair values		79.00%
Percentage of CDS derivative liability used in the determination of CDS fair values		70.00%
Percentage of CDS gross par outstanding using internally estimated reference obligation prices in determination of fair value		21.00%
Percentage of CDS liability using internally estimated reference obligation prices in determination of fair value		30.00%
Additional basis point fee need to receive for issuing a CDS on obligation		0.05%
Additional basis points fee increase on change of reference obligation spread		0.15%
Revised relative change ratio of CDS fee to cash market spread		73.20%
Estimated remaining life		8 years
Notional outstanding		2,776,103	11,281,777
Derivative liabilities		94,322	213,585
Percentage of profit margin	17.00%	17.00%	20.00%
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs		5.10%	7.60%
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Basis point fee received for issuing a CDS on reference obligation base fee		0.20%
Credit spread of reference obligation of a base transaction		0.80%
Relative change ratio of CDS fee to cash market spread		25.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Basis point fee received for issuing a CDS on reference obligation hypothetical fee		0.25%
Relative change ratio of CDS fee to cash market spread		35.00%
Credit spread of reference obligation of revised transaction		1.00%
Corporate Obligations [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments in corporate obligation securities classified as Level 3 in the fair value hierarchy		3,502	3,656
U.S. Agency Obligations [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments in corporate obligation securities classified as Level 3 in the fair value hierarchy		208	0
Other Commercial Asset-Backed [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments in corporate obligation securities classified as Level 3 in the fair value hierarchy		64,073	50,264
Fixed Income Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of investment portfolio valued using dealer quotes		11.00%	10.00%
Fixed Income Securities [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of investment portfolio valued using internal valuation models		1.00%	1.00%
Fixed Income Securities [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of investment portfolio valued using external pricing services		88.00%	89.00%
Collateralized Debt Obligations [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments in corporate obligation securities classified as Level 3 in the fair value hierarchy		0	6,482
European ABS Transactions [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of consolidated VIE debt obligations valued using unobservable inputs by asset class		1,329,985	2,956,501
US Commercial ABS Transaction [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of consolidated VIE debt obligations valued using unobservable inputs by asset class		$ 184,620
Credit Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
CVA percentage		29.20%	55.00%
Internal Credit Rating [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Revised relative change ratio of CDS fee to cash market spread		33.00%
Internal Credit Rating [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Full relative change ratio of CDS fee to cash market spread		100.00%

X

- Definition

Amount of credit risk valuation adjustment to derivative liabilities other than credit derivatives, to properly reflect the credit quality of the entity.

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- Definition

Weighted average discounted rate of estimated future premium payments to be paid by the VIEs.

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- Definition

Hypothetical base fee received on a credit derivative contract used in the description of the valuation processes in place for fair value measurement of credit derivatives.

+ References

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- Definition

Hypothetical base reference obligation spread used in the description of the valuation processes in place for fair value measurement of credit derivatives.

+ References

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- Definition

Hypothetical base relative change ratio for a credit derivative contract used in the description of the valuation processes in place for fair value measurement of credit derivatives.

+ References

No definition available.

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- Definition

Full relative change ratio comparable to certain default used in the description of the valuation processes in place for fair value measurement of credit derivative.

+ References

No definition available.

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- Definition

Hypothetical incremental credit derivative fee used in the description of the valuation processes in place for fair value measurement of credit derivatives.

+ References

No definition available.

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Hypothetical incremental credit derivative fee given a certain credit downgrade used in the description of the valuation processes in place for fair value measurement of credit derivative.

+ References

No definition available.

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- Definition

Hypothetical remaining contract life used in the description of the valuation processes in place for fair value measurement of credit derivatives.

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No definition available.

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- Definition

Hypothetical revised fee required on credit derivative contract used in the description of the valuation processes in place for fair value measurement of credit derivatives.

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- Definition

Hypothetical revised fee required on credit derivative given a certain credit downgrade used in the description of the valuation processes in place for fair value measurement of credit derivatives.

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No definition available.

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- Definition

Hypothetical revised reference obligation spread (second example) used in the description of the valuation processes in place for fair value measurement of credit derivatives.

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- Definition

Hypothetical revised relative change ratio used in the description of the valuation processes in place for fair value measurement of credit derivatives.

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- Definition

Fair Value of consolidated VIE debt obligations valued using unobservable inputs by asset class

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Fair value of investments in securities valued using unobservable inputs by asset class.

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- Definition

Percentage of credit derivative gross par outstanding using internally estimated reference obligation prices in determination of fair value.

+ References

No definition available.

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- Definition

Percentage of credit derivative liability using internally estimated reference obligation prices in determination of fair value.

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No definition available.

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- Definition

Percentage of credit derivatives gross par outstanding using third party reference obligation quotes in determination of fair value.

+ References

No definition available.

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- Definition

Percentage of credit derivatives liability using third party reference obligation quotes ion determination of fair value.

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- Definition

Credit valuation adjustment (CVA) as a percentage of the credit derivative liability calculated excluding the CVA.

+ References

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Investment portfolio valued using dealer quotes.

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Percentage of investment portfolio valued using external pricing services.

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Percentage of investment portfolio valued using internal valuation models.

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- Definition

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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Amount of credit risk valuation adjustment to derivative liabilities to properly reflect the credit quality of the entity.

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- Definition

Fair value before effects of master netting arrangements, of a 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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226000-175313



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

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- Definition

Ratio of an entity's operating income net of tax to its revenue, used as an input to measure fair value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

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