Derivative Financial Instruments - Offsetting of Derivative Assets - Derivative Liabilities, Financial Liabilities, and Collateral Held by Counterparty (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	$ 3,427,414	$ 7,319,966
Financial instruments	(3,336,577)	(7,297,360)
Net amount of liabilities in the consolidated balance sheet	90,837	22,606
Credit Suisse First Boston Mortgage Capital LLC
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,013,486	1,974,278
Financial instruments	(1,010,715)	(1,969,670)
Net amount of liabilities in the consolidated balance sheet	2,771	4,608
JP Morgan
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	258,472	300,912
Financial instruments	(254,369)	(300,912)
Net amount of liabilities in the consolidated balance sheet	4,103
Bank of America, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	261,862	1,758,690
Financial instruments	(261,862)	(1,758,690)
Barclays
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	386,318	677,419
Financial instruments	(368,749)	(676,685)
Net amount of liabilities in the consolidated balance sheet	17,569	734
Citibank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	72,786	403,003
Financial instruments	(72,786)	(402,806)
Net amount of liabilities in the consolidated balance sheet		197
Royal Bank of Canada
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	313,576	496,064
Financial instruments	(313,576)	(496,064)
BNP Paribas
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	98,446	349,172
Financial instruments	(97,098)	(349,172)
Net amount of liabilities in the consolidated balance sheet	1,348
Morgan Stanley Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	148,898	299,580
Financial instruments	(148,898)	(292,105)
Net amount of liabilities in the consolidated balance sheet		7,475
Wells Fargo Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	195,560	203,779
Financial instruments	(190,582)	(200,338)
Net amount of liabilities in the consolidated balance sheet	4,978	3,441
Goldman Sachs
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	625,583	853,147
Financial instruments	(617,942)	(850,918)
Net amount of liabilities in the consolidated balance sheet	7,641	2,229
Nomura
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	7,801
Net amount of liabilities in the consolidated balance sheet	7,801
Other
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	2,808	2,642
Net amount of liabilities in the consolidated balance sheet	2,808	2,642
Interest rate lock commitments
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	41,818	1,280
Net amount of liabilities in the consolidated balance sheet	$ 41,818	$ 1,280