Loan Sales and Servicing Activities - Summary of Cash Flows with Transferees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Cash flows:
Sales proceeds	$ 33,549,142	$ 26,168,605	$ 95,792,613	$ 70,706,054
Servicing fees received	425,390	363,121	1,233,153	1,048,099
Allowance for losses rollforward
Balance at beginning of quarter	82,025	68,671	85,788	73,991
Provision for losses	10,130	9,583	22,100	13,974
Charge-offs, net	(5,975)	(4,346)	(21,708)	(14,057)
Balance at end of quarter	86,180	$ 73,908	86,180	$ 73,908
Period end information:
Unpaid principal balance of loans outstanding	455,894,902		455,894,902		$ 410,393,342
30-89 days	18,746,088		18,746,088		17,301,961
90 days or more - Not in foreclosure	7,280,548		7,280,548		8,104,348
90 days or more - In foreclosure	1,391,013		1,391,013		693,934
90 days or more - Foreclosed	3,888		3,888		2,928
Loans in bankruptcy	$ 2,037,245		$ 2,037,245		$ 1,762,324