CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities
Net income	$ 165,560	$ 123,120
Adjustments to reconcile net income to net cash used in operating activities:
Provisions for credit losses	75,511	74,395
Income tax expense	95,724	71,181
Amortization of brokered deposit placement fee	4,339	5,179
Amortization of ABCP Facility upfront fee	668	502
Amortization of deferred loan origination costs and fees, net	4,069	2,720
Net amortization of discount on investments	872	793
Interest income on tax indemnification receivable	(3,427)	(4,066)
Depreciation of premises and equipment	5,365	2,295
Amortization of acquired intangibles	234	261
Stock-based compensation expense	15,500	12,548
Unrealized losses (gains) on derivatives and hedging activities, net	10,833	(835)
Other adjustments to net income, net	2,998	1,101
Changes in operating assets and liabilities:
Increase in accrued interest receivable	(324,684)	(277,582)
Decrease in restricted cash and investments, net	4,004	2,053
Increase in other interest-earning assets	588	1,290
Decrease in tax indemnification receivable	29,817	29,816
Increase in other assets	(20,586)	(14,591)
Decrease in income taxes payable, net	(139,775)	(149,193)
Increase in accrued interest payable	3,275	2,924
Decrease in payable due to entity that is a subsidiary of Navient	(1,244)	(808)
(Decrease) increase in other liabilities	(35,267)	7,976
Total adjustments	(271,186)	(232,041)
Total net cash used in operating activities	(105,626)	(108,921)
Investing activities
Loans acquired and originated	(2,347,344)	(2,234,556)
Net proceeds from sales of loans held for investment	3,472	5,736
Proceeds from claim payments	24,907	33,892
Net decrease in loans held for investment	980,234	624,040
Increase in restricted cash and investments - variable interest entities	(12,753)	(8,369)
Purchases of available-for-sale securities	(40,124)	(23,362)
Proceeds from sales and maturities of available-for-sale securities	16,976	15,492
Total net cash used in investing activities	(1,374,632)	(1,587,127)
Financing activities
Brokered deposit placement fee	(5,329)	(2,875)
Net decrease in certificates of deposit	308,069	56,272
Net increase in other deposits	51,447	322,959
Issuance costs for collateralized borrowings	0	(386)
Borrowings collateralized by loans in securitization trusts - issued	767,244	499,393
Borrowings collateralized by loans in securitization trusts - repaid	(262,567)	(40,618)
Issuance costs for unsecured debt offering	(423)	0
Unsecured debt issued	197,000	0
Borrowings under ABCP Facility	0	26,325
Repayment of borrowings under ABCP Facility	0	(526,500)
Fees paid on ABCP Facility	(1,259)	(1,444)
Redemption of Preferred Stock Series A	(165,000)	0
Preferred stock dividends paid	(9,549)	(10,382)
Net cash provided by financing activities	879,633	322,744
Net decrease in cash and cash equivalents	(600,625)	(1,373,304)
Cash and cash equivalents at beginning of period	1,918,793	2,416,219
Cash and cash equivalents at end of period	1,318,168	1,042,915
Cash disbursements made for:
Interest	121,601	75,165
Income taxes paid	139,828	149,173
Income taxes refunded	$ (833)	$ (86)