Condensed Consolidated Statements of Cash Flows - USD ($)		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Statement of Cash Flows [Abstract]
Consolidated net loss		$ (61,947,000)	$ (113,700,000)
Adjustments to reconcile consolidated net loss to net cash used for operating activities:
Net fair value adjustments of loans, loans held for sale, notes and certificates		11,363,000	1,684,000
Change in fair value of loan servicing liabilities		(1,947,000)	(3,028,000)
Change in fair value of loan servicing assets		16,083,000	7,092,000
Stock-based compensation, net		54,692,000	46,434,000
Excess tax benefit from share-based awards		0	62,000
Goodwill impairment charge	[1]	0	37,050,000
Depreciation and amortization		32,405,000	21,374,000
Gain on sales of loans		(25,306,000)	(10,531,000)
Other, net		2,093,000	758,000
Purchase of loans held for sale		(4,240,099,000)	(3,653,191,000)
Principal payments received on loans held for sale		24,860,000	2,860,000
Proceeds from sales of whole loans		3,955,878,000	3,635,330,000
Purchase of loans held for sale by consolidated VIE		(491,414,000)	0
Proceeds from sale of securities by consolidated VIE, net of underwriting fees and costs		569,443,000	0
Net change in operating assets and liabilities:
Accrued interest receivable		4,174,000	(2,720,000)
Other assets		(13,860,000)	(1,570,000)
Due from related parties		197,000	120,000
Accounts payable		(3,810,000)	1,888,000
Accrued interest payable		(5,596,000)	3,835,000
Accrued expenses and other liabilities		11,963,000	18,507,000
Net cash used for operating activities		(160,828,000)	(7,746,000)
Cash Flows from Investing Activities:
Purchases of loans		(1,407,664,000)	(2,086,228,000)
Principal payments received on loans		1,863,338,000	1,783,763,000
Proceeds from recoveries and sales of charged-off loans		34,808,000	27,451,000
Proceeds from sales of whole loans		2,118,000	22,274,000
Purchases of securities available for sale		(90,174,000)	(40,123,000)
Proceeds from maturities of securities available for sale		191,504,000	59,735,000
Proceeds from paydowns of asset-backed securities related to Company- sponsored securitization transactions		2,268,000	0
Investment in Cirrix Capital		0	(10,000,000)
Net change in restricted cash		(5,034,000)	(58,722,000)
Purchases of property, equipment and software, net		(31,751,000)	(39,044,000)
Net cash provided by (used for) investing activities		559,413,000	(340,894,000)
Cash Flows from Financing Activities:
Change in payable to investors		(31,991,000)	8,214,000
Proceeds from issuances of notes and certificates		1,389,999,000	2,041,746,000
Proceeds from secured borrowings		0	22,274,000
Repayments of secured borrowings		0	(22,274,000)
Principal payments and retirements of notes and certificates		(1,863,041,000)	(1,770,779,000)
Payments on notes and certificates from recoveries/sales of related charged-off loans		(34,550,000)	(26,871,000)
Repurchase of common stock		0	(19,485,000)
Proceeds from stock option exercises and other		14,265,000	10,580,000
Proceeds from issuance of common stock for ESPP		2,856,000	2,516,000
Excess tax benefit from share-based awards		0	(62,000)
Purchase of noncontrolling interests in consolidated VIE		(6,307,000)	0
Return of capital to noncontrolling interests in consolidated VIE		(999,000)	0
Dividends paid to noncontrolling interests in consolidated VIE		(38,000)	0
Other financing activities		0	17,000
Net cash (used for) provided by financing activities		(529,806,000)	245,876,000
Net Decrease in Cash and Cash Equivalents		(131,221,000)	(102,764,000)
Cash and Cash Equivalents, Beginning of Period		515,602,000	623,531,000
Cash and Cash Equivalents, End of Period		384,381,000	520,767,000
Supplemental Cash Flow Information:
Cash paid for interest		454,026,000	519,690,000
Accruals for property, equipment and software		1,360,000	2,610,000
Beneficial interests retained by consolidated VIE		36,065,000	0
Noncontrolling interests’ contribution of beneficial interests in consolidated VIE		$ 7,722,000	$ 0

[1] Prior period amounts have been reclassified to conform to the current period presentation. See “Notes to Condensed Consolidated Financial Statements – Note 1. Basis of Presentation” for additional information.