Basis of Presentation and Significant Accounting Policies (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Risks and Uncertainties [Abstract]
Percentage of active forbearance loan borrowers		0.90%		0.90%
Percentage of active forbearance loan borrowers paying monthly payment		17.90%		17.90%
Investments in RMBS [Abstract]
Sale of RMBS, settled after period end				$ (67,734,000)	$ 0
Purchase of RMBS, settled after period end				56,362,000	0
Cash and Cash Equivalents and Restricted Cash [Abstract]
Restricted cash		$ 16,047,000		16,047,000		$ 12,861,000
Variation margin		80,800,000		80,800,000		45,600,000
Realized gain (loss) on RMBS, net [Abstract]
Gain on RMBS		0	$ 2,820,000	50,000	5,484,000
Loss on RMBS		(46,036,000)	(1,837,000)	(59,308,000)	(2,407,000)
Net realized gain (loss) on RMBS	[1]	(46,036,000)	$ 983,000	(59,258,000)	$ 3,077,000
Derivatives [Member]
Cash and Cash Equivalents and Restricted Cash [Abstract]
Restricted cash		2,200,000		2,200,000		664,000
Repurchase Agreements [Member]
Cash and Cash Equivalents and Restricted Cash [Abstract]
Restricted cash		13,800,000		13,800,000		12,200,000
Receivables and Other Assets [Member] | RMBS [Member]
Investments in RMBS [Abstract]
Interest receivable		$ 2,400,000		$ 2,400,000		$ 2,300,000

[1] Reclassified from accumulated other comprehensive income into earnings.