Income Taxes - Reconciliation of GAAP Net Income to Estimated REIT Taxable Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Disclosure [Abstract]
GAAP net income (loss)	$ (58,591)	$ (66,434)	$ (69,174)	$ 71,327	$ (125,025)	$ 2,153
Book to tax differences:
TRS income	(6)		(59)		(7)	(66)
Premium amortization expense	(36)		(28)		(78)	(76)
Agency Securities, trading	249,022		(19,183)		503,411	43,403
U.S. Treasury Securities	33,983		0		112,370	28
Changes in interest rate contracts	(204,744)		88,542		(455,644)	(33,653)
(Gain) loss on Security Sales	7,501		0		7,501	(7,354)
Amortization of deferred hedging costs	(36,716)		(39,998)		(76,296)	(81,865)
Other	610		419		1,160	837
Estimated REIT taxable loss	$ (8,977)		$ (39,481)		$ (32,608)	$ (76,593)