Derivative Financial Instruments - Offsetting of Derivative Assets - Derivative Liabilities, Financial Liabilities, and Collateral Held by Counterparty (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	$ 7,385,387	$ 8,733,656
Financial instruments	(7,351,846)	(8,692,756)
Net amount of liabilities in the consolidated balance sheet	33,541	40,900
Bank of America, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,275,935	1,294,213
Financial instruments	(1,262,608)	(1,294,213)
Net amount of liabilities in the consolidated balance sheet	13,327
Atlas Securitized Products, L.P.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	2,339,762	1,938,756
Financial instruments	(2,339,762)	(1,938,756)
Wells Fargo Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	542,679	795,119
Financial instruments	(541,545)	(789,305)
Net amount of liabilities in the consolidated balance sheet	1,134	5,814
Royal Bank of Canada
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	633,971	785,597
Financial instruments	(633,971)	(785,597)
JPMorgan Chase Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	808,309	1,220,822
Financial instruments	(808,175)	(1,214,559)
Net amount of liabilities in the consolidated balance sheet	134	6,263
BNP Paribas
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	346,078	568,790
Financial instruments	(345,257)	(568,790)
Net amount of liabilities in the consolidated balance sheet	821
Citibank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	470,812	455,426
Financial instruments	(470,812)	(455,426)
Barclays Capital
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	80,650	258,559
Financial instruments	(80,434)	(254,750)
Net amount of liabilities in the consolidated balance sheet	216	3,809
Santander US Capital Markets LLC
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	245,158	282,077
Financial instruments	(240,555)	(282,077)
Net amount of liabilities in the consolidated balance sheet	4,603
Goldman Sachs
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	98,732	336,894
Financial instruments	(97,950)	(336,624)
Net amount of liabilities in the consolidated balance sheet	782	270
Morgan Stanley Bank, N.A.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	320,702	472,659
Financial instruments	(320,396)	(472,659)
Net amount of liabilities in the consolidated balance sheet	306
Nomura Corporate Funding Americas
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	134,739	175,000
Financial instruments	(134,739)	(175,000)
Mizuho Bank, Ltd.
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	75,642	125,000
Financial instruments	(75,642)	(125,000)
Federal National Mortgage Association
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,904
Net amount of liabilities in the consolidated balance sheet	1,904
Others
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	8,368	1,363
Net amount of liabilities in the consolidated balance sheet	8,368	1,363
PennyMac Mortgage Investment Trust
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	1,038
Net amount of liabilities in the consolidated balance sheet	1,038
Interest rate lock commitments
Derivative liabilities:
Net amounts of liabilities presented in the consolidated balance sheet	908	23,381
Net amount of liabilities in the consolidated balance sheet	$ 908	$ 23,381