Additional Information about Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013
Assets and Liabilities At Fair Value On Recurring Basis [Line Items]
Loans, Fair value at December 31, 2012	$ 781,215
Loans, Purchases of Loans	2,064,628
Loans, Issuances of Notes and Certificates
Loans at fair value, Principal repayments	(511,232)
Loans, Whole Loan sales	(446,224)
Loans, Recoveries from sale and collection of charged-off loans	(1,716)
Loans, Carrying value before fair value adjustments	1,886,671
Loans, Fair valuation adjustments, included in earnings	(57,629)
Loans, Fair value at December 31, 2013	1,829,042
Notes and Certificates, Fair value at December 31, 2012	785,316
Notes and Certificates, Purchases of Loans
Notes and Certificates, Issuances of Notes and Certificates	1,618,269
Notes and Certificates, Principal repayments	(504,330)
Notes and Certificates, Whole Loan sales
Notes and Certificates, Recoveries from sale and collection of charged-off loans	(1,669)
Notes and Certificates, Carrying value before fair value adjustments	1,897,586
Notes and Certificates, Fair valuation adjustments, included in earnings	(57,596)
Notes and Certificates, Fair value at December 31, 2013	$ 1,839,990

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Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Asset Principal Amount of Loan before Fair Value Adjustment

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Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Asset Recoveries from Sale and Collection of Charged Off Loans

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Principal amount of notes before fair value adjustment.

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Recoveries from Sale and Collection of Charged Off Loans for Notes and Certificates

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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of issuances of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sales of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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