CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net income	$ 241,931	$ 180,085
Adjustments to reconcile net income to net cash used in operating activities:
Provisions for credit losses	130,441	116,179
Income tax expense	136,341	118,530
Amortization of brokered deposit placement fee	6,831	7,766
Amortization of ABCP Facility upfront fee	995	866
Amortization of deferred loan origination costs and fees, net	6,122	4,304
Net amortization of discount on investments	1,504	1,387
Loss (income) on tax indemnification receivable	311	(14,386)
Depreciation of premises and equipment	8,194	6,896
Amortization of acquired intangibles	351	747
Stock-based compensation expense	21,773	17,950
Unrealized losses (gains) on derivatives and hedging activities, net	6,931	(1,881)
Other adjustments to net income, net	4,601	2,540
Changes in operating assets and liabilities:
Increase in accrued interest receivable	(506,451)	(430,441)
Decrease in restricted cash and investments, net	5,701	1,564
Decrease in other interest-earning assets	17,811	7,562
Decrease in tax indemnification receivable	44,725	44,725
Increase in other assets	(53,276)	(22,879)
Decrease in income taxes payable, net	(217,235)	(201,338)
Increase in accrued interest payable	15,240	10,202
(Decrease) increase in payable due to entity that is a subsidiary of Navient	(305)	658
Increase in other liabilities	6,143	7,131
Total adjustments	(363,252)	(321,918)
Total net cash used in operating activities	(121,321)	(141,833)
Investing activities
Loans acquired and originated	(4,314,711)	(4,072,631)
Net proceeds from sales of loans held for investment	5,497	7,912
Proceeds from claim payments	34,759	49,742
Net decrease in loans held for investment	1,488,087	953,715
Increase in restricted cash and investments - variable interest entities	(18,608)	(11,840)
Purchases of available-for-sale securities	(55,569)	(40,767)
Proceeds from sales and maturities of available-for-sale securities	29,452	26,318
Total net cash used in investing activities	(2,831,093)	(3,087,551)
Financing activities
Brokered deposit placement fee	(9,668)	(3,953)
Net increase in certificates of deposit	1,087,486	481,623
Net increase in other deposits	516,343	961,123
Issuance costs for collateralized borrowings	0	(1,351)
Borrowings collateralized by loans in securitization trusts - issued	767,245	1,104,551
Borrowings collateralized by loans in securitization trusts - repaid	(397,106)	(106,567)
Issuance costs for unsecured debt offering	(1,057)	0
Unsecured debt issued	197,000	0
Borrowings under ABCP Facility	300,000	376,325
Repayment of borrowings under ABCP Facility	0	(526,500)
Fees paid on ABCP Facility	(1,281)	(1,450)
Redemption of Preferred Stock Series A	(165,000)	0
Preferred stock dividends paid	(12,577)	(15,698)
Net cash provided by financing activities	2,281,385	2,268,103
Net decrease in cash and cash equivalents	(671,029)	(961,281)
Cash and cash equivalents at beginning of period	1,918,793	2,416,219
Cash and cash equivalents at end of period	1,247,764	1,454,938
Cash disbursements made for:
Interest	191,488	119,812
Income taxes paid	216,321	201,218
Income taxes refunded	$ (986)	$ (86)