Fair Value of Assets and Liabilities - Additional Information about Servicing Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Servicing Assets, Changes in fair value due to:
Fair value at beginning of period			$ 56,347
Fair value at end of period	$ 58,728		58,728
Fair Value, Measurements, Recurring
Servicing Assets, Changes in fair value due to:
Fair value at beginning of period	54,113	$ 92,825	56,347	$ 89,680
Issuances	17,968	1,755	25,203	19,336
Change in fair value, included in Marketplace revenue	(12,763)	(25,062)	(24,600)	(34,670)
Other net changes included in Deferred revenue	(590)	(4,003)	1,778	(8,831)
Fair value at end of period	58,728	65,515	58,728	65,515
Asset-backed subordinated securities related to Company-sponsored Structured Program transactions
Servicing Liabilities, Changes in fair value due to:
Fair value at beginning of period	59,754	103,511	66,654	110,796
Additions	379	2,427	957	26,012
Redemptions	(2,224)	(376)	(2,224)	(376)
Cash received	(15,620)	(17,808)	(29,814)	(34,074)
Change in unrealized gain (loss)	1,733	2,131	4,858	(3,125)
Accrued interest	1,574	2,194	2,695	3,826
Reversal of (impairment on) securities available for sale	322	3,511	2,792	(7,469)
Fair value at end of period	$ 45,918	$ 95,590	$ 45,918	$ 95,590

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Accrued Interest

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Provision for Credit Recovery (Loss) Expense

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No definition available.

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Retirements

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- Definition

Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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- Definition

Amount of purchases 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 settlements 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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Fair value 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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- Definition

The value of new servicing assets, subsequently measured at fair value, acquired or created during the current period through purchases or from transfers of financial assets.

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-Publisher FASB
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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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Amount of increase (decrease) in fair value from changes in the inputs, assumptions, or model used to calculate the fair value of the contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Amount of increase (decrease) in fair value from changes classified as other for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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