Loan Sales and Servicing Activities - Summary of Cash Flows with Transferees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Cash flows:
Sales proceeds	$ 21,651,096	$ 16,215,098	$ 60,061,205	$ 67,056,886
Servicing fees received	303,224	242,622	853,962	676,384
Allowance for losses rollforward
Balance at beginning of period	70,070	66,143	78,992	120,940
Reversal of provision for losses	(2,554)	(820)	(7,603)	(52,113)
Charge-offs, net	(1,872)	(1,610)	(5,745)	(5,114)
Balance at end of period	65,644	$ 63,713	65,644	$ 63,713
Period end information:
Unpaid principal balance of loans outstanding	333,372,910		333,372,910		$ 295,032,674
30-89 days	12,534,532		12,534,532		11,019,194
90 days or more - Not in foreclosure	6,176,470		6,176,470		6,548,849
90 days or more - In foreclosure	748,004		748,004		834,155
90 days or more - Foreclosed	8,172		8,172		12,905
Bankruptcy	$ 1,319,689		$ 1,319,689		$ 1,143,484