Accrued Expenses and Other Liabilities (Detail) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Contingent liabilities		$ 101,889	$ 129,887
Accrued expenses		30,667	21,317
Accrued compensation		16,438	30,549
Transaction fee refund reserve		15,088	14,528
Deferred rent		14,831	14,734
Loan trailing fee liability, at fair value		8,824	8,432
Deferred revenue		4,315	3,415
Payable to issuing banks		1,015	1,894
Loan servicing liabilities, at fair value		475	833
Other		2,975	2,791
Total accrued expenses and other liabilities	[1]	$ 196,517	$ 228,380

[1] Includes amounts in consolidated variable interest entities (VIEs) presented separately in the table below.