CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net income	$ 184,439	$ 174,068
Adjustments to reconcile net income to net cash used in operating activities:
Provisions for loan losses	59,673	55,071
Income tax expense	109,865	115,502
Amortization of brokered deposit placement fee	8,006	7,548
Amortization of asset-backed commercial paper upfront fee	1,790	0
Amortization of deferred loan origination costs and fees, net	2,563	1,446
Net accretion of discount on borrowings	108	0
Net accretion of underwriter fees on borrowings	108	0
Net amortization of discount on investments	1,332	433
Depreciation of premises and equipment	5,427	4,289
Amortization of acquired intangibles	1,110	2,783
Stock-based compensation expense	16,423	20,127
Unrealized (gains)/losses on derivative and hedging activities, net	(1,985)	1,307
Gains on sale of loans, net	(76,874)	(120,963)
Changes in operating assets and liabilities:
Net decrease in loans held for sale	55	6,448
Origination of loans held for sale	(55)	(6,448)
Increase in accrued interest receivable	(316,263)	(220,273)
Increase in restricted cash and investments - other	(2,596)	(1,503)
Decrease (increase) in other interest-earning assets	24,875	(46,333)
Decrease in tax indemnification receivable	39,607	29,816
Increase in other assets	(18,022)	(18,918)
Decrease in income tax payable, net	(176,172)	(294,116)
Increase in accrued interest payable	7,227	2,639
(Decrease) increase in payable due to entity that is a subsidiary of Navient	(5,368)	18,114
Increase in other liabilities	5,895	30,741
Total adjustments	(313,271)	(412,290)
Total net cash used in operating activities	(128,832)	(238,222)
Investing activities
Loans acquired and originated	(3,786,946)	(3,535,740)
Net proceeds from sales of loans held for investment	790,094	1,994,017
Proceeds from claim payments	91,000	88,251
Net decrease (increase) in loans held for investment	672,665	476,955
Increase in restricted cash and investments - variable interest entities	(18,205)	0
Purchases of available-for-sale securities	(50,062)	(55,928)
Proceeds from sales and maturities of available-for-sale securities	26,222	7,337
Total net cash used in investing activities	(2,275,232)	(1,025,108)
Financing activities
Brokered deposit placement fee	(477)	(5,533)
Net increase (decrease) in certificates of deposit	161,096	(614,953)
Net (decrease) increase in other deposits	(129,412)	804,874
Borrowings collateralized by loans in securitization trusts - issued	620,681	0
Borrowings collateralized by loans in securitization trusts - repaid	(27,195)	0
Borrowings under ABCP facility	713,746	0
Repayment of borrowings under ABCP facility	(3,741)	0
Fees paid on ABCP facility	(104)	0
Net decrease in deposits with entity that is a subsidiary of Navient	0	(5,633)
Special cash contribution from Navient	0	472,718
Net capital contributions from entity that is a subsidiary of Navient	0	7,448
Excess tax benefit from the exercise of stock-based awards	6,093	0
Preferred stock dividends paid	(14,606)	(8,078)
Net cash provided by financing activities	1,326,081	650,843
Net decrease in cash and cash equivalents	(1,077,983)	(612,487)
Cash and cash equivalents at beginning of period	2,359,780	2,182,865
Cash and cash equivalents at end of period	1,281,797	1,570,378
Cash disbursements made for:
Interest	79,917	64,987
Income taxes paid	$ 171,114	$ 294,116