Investment in Securities (Unrealized Loss Positions Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	$ 374,926	$ 720,249
Unrealized Losses, Less than 12 Months	(13,906)	(60,343)
Fair Value, Greater than 12 Months	487,617	365,355
Unrealized Losses, Greater than 12 Months	(69,649)	(66,704)
Fair Value, Total	862,543	1,085,604
Unrealized Loss, Total	(83,555)	(127,047)
Agency RMBS
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	281,597	577,047
Unrealized Losses, Less than 12 Months	(10,070)	(51,817)
Fair Value, Greater than 12 Months	440,429	326,223
Unrealized Losses, Greater than 12 Months	(58,421)	(57,564)
Fair Value, Total	722,026	903,270
Unrealized Loss, Total	(68,491)	(109,381)
Non-Agency RMBS
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	32,147	46,644
Unrealized Losses, Less than 12 Months	(2,724)	(5,205)
Fair Value, Greater than 12 Months	31,886	26,194
Unrealized Losses, Greater than 12 Months	(7,850)	(4,959)
Fair Value, Total	64,033	72,838
Unrealized Loss, Total	(10,574)	(10,164)
CLOs
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	0	6,035
Unrealized Losses, Less than 12 Months	0	(466)
Fair Value, Greater than 12 Months	14,157	12,212
Unrealized Losses, Greater than 12 Months	(2,531)	(3,488)
Fair Value, Total	14,157	18,247
Unrealized Loss, Total	(2,531)	(3,954)
Other Securities
Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	61,182	90,523
Unrealized Losses, Less than 12 Months	(1,112)	(2,855)
Fair Value, Greater than 12 Months	1,145	726
Unrealized Losses, Greater than 12 Months	(847)	(693)
Fair Value, Total	62,327	91,249
Unrealized Loss, Total	$ (1,959)	$ (3,548)