CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Operating activities
Net income	$ 1,160,513	$ 880,690	$ 578,276
Adjustments to reconcile net income to net cash used in operating activities:
Provisions for credit losses	(32,957)	93,133	354,249
Deferred tax provision (benefit)	55,372	72,776	(9,714)
Amortization of brokered deposit placement fee	15,516	19,401	17,788
Amortization of Secured Borrowing Facility upfront fee	2,415	2,976	1,117
Amortization of deferred loan origination costs and loan premium/(discounts), net	16,103	24,152	13,049
Net amortization of discount on investments	7,310	6,350	2,069
Reduction of tax indemnification receivable	10,445	9,066	11,649
Depreciation of premises and equipment	16,043	15,066	14,669
Stock-based compensation expense	30,649	36,464	30,600
Unrealized (gains) losses on derivative and hedging activities, net	23,249	(10,333)	(19,046)
Gains on sale of loans, net	(548,315)	(238,315)	0
Gain on sale of Upromise subsidiary, net	0	(11,331)	0
Other adjustments to net income, net	(23,410)	8,810	3,724
Changes in operating assets and liabilities:
Increase in accrued interest receivable	(743,757)	(876,703)	(963,885)
Increase in non-marketable securities	(9,969)	(839)	(10,700)
Decrease (increase) in other interest-earning assets	33,219	9,690	(25,407)
Increase in other assets	(123,268)	(50,454)	(3,091)
Increase (decrease) in income tax payable, net	72,191	(45,611)	(30,191)
(Decrease) increase in accrued interest payable	(13,672)	(14,602)	13,817
Decrease in Upromise member accounts due to sale	0	(193,840)	0
Increase in other liabilities	2,801	80,785	5,386
Total adjustments	(1,210,035)	(1,063,359)	(593,917)
Total net cash used in operating activities	(49,522)	(182,669)	(15,641)
Investing activities
Loans acquired and originated	(5,511,845)	(5,378,283)	(6,138,105)
Net proceeds from sales of loans held for investment	4,642,505	3,875,737	0
Proceeds from claim payments	19,386	28,709	42,869
Net decrease in loans held for investment	3,845,990	3,832,991	4,094,021
Purchases of available-for-sale securities	(1,257,129)	(2,083,261)	(356,414)
Proceeds from sales and maturities of available-for-sale securities	865,766	654,515	50,915
Proceeds from the sale of Upromise subsidiary, net	0	16,922	0
Total net cash provided by (used in) investing activities	2,604,673	947,330	(2,306,714)
Financing activities
Brokered deposit placement fee	(12,565)	(4,810)	(27,978)
Net (decrease) increase in certificates of deposit	(2,130,728)	(2,428,094)	4,349,741
Net increase in other deposits	393,306	704,382	923,793
Borrowings collateralized by loans in securitization trusts - issued	1,585,125	1,338,641	1,105,594
Borrowings collateralized by loans in securitization trusts - repaid	(1,143,738)	(1,003,327)	(1,042,892)
Borrowings under Secured Borrowing Facility	0	0	297,800
Repayment of borrowings under Secured Borrowing Facility	0	(289,230)	(8,570)
Fees paid - Secured Borrowing Facility	(2,846)	(3,256)	(1,116)
Unsecured debt issued	492,135	495,000	0
Unsecured debt repaid	(202,784)	0	0
Preferred stock dividends paid	(4,736)	(9,734)	(16,837)
Repurchase of Series B Preferred Stock	0	(68,055)	0
Common stock dividends paid	(60,462)	(46,351)	(51,114)
Common stock repurchased	(1,530,683)	(558,167)	(167,201)
Net cash (used in) provided by financing activities	(2,619,516)	(1,875,712)	5,361,220
Net (decrease) increase in cash, cash equivalents and restricted cash	(64,365)	(1,111,051)	3,038,865
Cash, cash equivalents and restricted cash at beginning of year	4,609,709	5,720,760	2,681,895
Cash, cash equivalents and restricted cash at end of year	4,545,344	4,609,709	5,720,760
Cash disbursements made for:
Interest	359,684	517,444	666,018
Income taxes paid	261,473	248,122	201,792
Income taxes refunded	(8,614)	(6,219)	(853)
Reconciliation of the Consolidated Statements of Cash Flows to the Consolidated Balance Sheets:
Cash and cash equivalents	4,334,603	4,455,292	5,563,877
Restricted cash	210,741	154,417	156,883
Total cash, cash equivalents and restricted cash	4,545,344	4,609,709	5,720,760
Collateralized Securities
Financing activities
Issuance costs for collateralized borrowings and unsecured debt offering	0	(1,402)	0
Unsecured Debt
Financing activities
Issuance costs for collateralized borrowings and unsecured debt offering	$ (1,540)	$ (1,309)	$ 0