Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Future [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TBA securities	$ 56,000	$ 0
Derivative Liability	0	15,000
Interest Rate Swaption [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	293,000	290,000
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	2,000	0
Purchases Of TBAs And Forward Settling Agency Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | TBA and Forward Settling Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TBA securities	(266,000)	(27,000)
Purchases Of TBAs And Forward Settling Agency Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Sale Of TBA And Forward Settling Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TBA securities	(266,000)
Securities Sold under Agreements to Repurchase	$ 36,262,000	47,381,000
Transfers between hierarchy levels	no
Agency securities	$ 39,346,000	52,396,000
Non-Agency Securities, at Fair Value	682,000	843,000
Financial Instruments, Owned, Other, at Fair Value	757,000	974,000
U.S. Treasury securities	353,000	471,000
TBA securities	(617,000)	(317,000)
Derivative Liability	99,000	86,000
Debt of consolidated variable interest entities, at fair value	95,000	126,000
Obligation to return securities borrowed under reverse repurchase agreements, at fair value	6,534,000	9,697,000
Interest rate swaps	617,000	317,000
Mortgage Credit Investment Fund Limited Partnership	25,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	409,000	471,000
Total liabilities	6,534,000	9,712,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	41,465,000	54,738,000
Total liabilities	194,000	197,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Sale Of TBA And Forward Settling Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	$ 99,000	$ 71,000