Investment in Securities (Unrealized Loss Positions Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	$ 1,094,937	$ 153,786
Unrealized Losses, Less than 12 Months	(16,006)	(4,358)
Fair Value, Greater than 12 Months	44,888	4,627
Unrealized Losses, Greater than 12 Months	(6,414)	(1,523)
Fair Value, Total	1,139,825	158,413
Unrealized Loss, Total	(22,420)	(5,881)
Agency RMBS
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	1,083,017	126,926
Unrealized Losses, Less than 12 Months	(15,190)	(981)
Fair Value, Greater than 12 Months	39,124	832
Unrealized Losses, Greater than 12 Months	(1,815)	(44)
Fair Value, Total	1,122,141	127,758
Unrealized Loss, Total	(17,005)	(1,025)
Non-Agency RMBS
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	11,296	20,474
Unrealized Losses, Less than 12 Months	(802)	(2,616)
Fair Value, Greater than 12 Months	4,462	2,599
Unrealized Losses, Greater than 12 Months	(1,850)	(348)
Fair Value, Total	15,758	23,073
Unrealized Loss, Total	(2,652)	(2,964)
CLOs
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	624	5,279
Unrealized Losses, Less than 12 Months	(14)	(753)
Fair Value, Greater than 12 Months	1,302	1,196
Unrealized Losses, Greater than 12 Months	(2,749)	(1,131)
Fair Value, Total	1,926	6,475
Unrealized Loss, Total	$ (2,763)	(1,884)
Other Securities
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months		1,107
Unrealized Losses, Less than 12 Months		(8)
Fair Value, Greater than 12 Months		0
Unrealized Losses, Greater than 12 Months		0
Fair Value, Total		1,107
Unrealized Loss, Total		$ (8)