Derivative Financial Instruments - Offsetting of Derivative Assets - Derivative Liabilities, Financial Liabilities, and Collateral Held by Counterparty (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	$ 7,080,241	$ 8,733,656
Financial instruments	(7,064,948)	(8,692,756)
Net amount of liabilities in the consolidated balance sheet	15,293	40,900
Bank of America, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,218,402	1,294,213
Financial instruments	(1,211,436)	(1,294,213)
Net amount of liabilities in the consolidated balance sheet	6,966
Atlas Securitized Products, L.P.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,618,676	1,938,756
Financial instruments	(1,618,676)	(1,938,756)
Wells Fargo Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	624,073	795,119
Financial instruments	(622,836)	(789,305)
Net amount of liabilities in the consolidated balance sheet	1,237	5,814
Royal Bank of Canada
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	792,680	785,597
Financial instruments	(792,680)	(785,597)
JPMorgan Chase Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	895,111	1,220,822
Financial instruments	(894,816)	(1,214,559)
Net amount of liabilities in the consolidated balance sheet	295	6,263
BNP Paribas
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	408,559	568,790
Financial instruments	(408,559)	(568,790)
Citibank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	557,694	455,426
Financial instruments	(557,694)	(455,426)
Barclays Capital
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	140,864	258,559
Financial instruments	(140,864)	(254,750)
Net amount of liabilities in the consolidated balance sheet		3,809
Santander US Capital Markets LLC
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	244,651	282,077
Financial instruments	(243,706)	(282,077)
Net amount of liabilities in the consolidated balance sheet	945
Goldman Sachs
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	232,012	336,894
Financial instruments	(232,012)	(336,624)
Net amount of liabilities in the consolidated balance sheet		270
Morgan Stanley Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	166,669	472,659
Financial instruments	(166,669)	(472,659)
Nomura Corporate Funding Americas
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	125,000	175,000
Financial instruments	(125,000)	(175,000)
Mizuho Bank, Ltd.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	50,000	125,000
Financial instruments	(50,000)	(125,000)
Federal National Mortgage Association
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,126
Net amount of liabilities in the consolidated balance sheet	1,126
Others
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	2,203	1,363
Net amount of liabilities in the consolidated balance sheet	2,203	1,363
PennyMac Mortgage Investment Trust
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	741
Net amount of liabilities in the consolidated balance sheet	741
Interest rate lock commitments
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,780	23,381
Net amount of liabilities in the consolidated balance sheet	$ 1,780	$ 23,381