Investment in Securities (Summary of Investment Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Securities, Available-for-sale [Line Items]
Net Amortization	$ 25,066	$ 32,578	$ 41,681
Interest Income	282,218	175,505	173,531
Level 3
Securities, Available-for-sale [Line Items]
Assets, Transfers into Level 3	35,266	13,797	92,143
Agency RMBS
Securities, Available-for-sale [Line Items]
Coupon Interest	50,032	58,495	59,987
Net Amortization	(10,410)	(24,642)	(31,975)
Interest Income	39,622	33,853	28,012
Non-Agency RMBS and CMBS
Securities, Available-for-sale [Line Items]
Coupon Interest	18,887	13,987	15,257
Net Amortization	267	3,423	5,775
Interest Income	19,154	17,410	21,032
CLOs
Securities, Available-for-sale [Line Items]
Coupon Interest	5,963	10,701	14,103
Net Amortization	(1,605)	(1,035)	3,529
Interest Income	4,358	9,666	17,632
Other Securities
Securities, Available-for-sale [Line Items]
Coupon Interest	20,665	17,332	11,545
Net Amortization	(5,876)	(5,538)	(4,986)
Interest Income	14,789	11,794	6,559
Securities Investment [Member]
Securities, Available-for-sale [Line Items]
Coupon Interest	95,547	100,515	100,892
Net Amortization	(17,624)	(27,792)	(27,657)
Interest Income	$ 77,923	$ 72,723	$ 73,235