Investment in Securities (Summary of Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Securities, Available-for-sale [Line Items]
Interest Income	$ 78,592	$ 40,146	$ 192,388	$ 126,115
Level 3
Securities, Available-for-sale [Line Items]
Assets, Transfers into Level 3	8,207	11,040	35,984	12,922
Agency RMBS
Securities, Available-for-sale [Line Items]
Coupon Interest	11,950	14,797	39,227	43,449
Net Amortization	(1,169)	(9,551)	(9,199)	(20,123)
Interest Income	10,781	5,246	30,028	23,326
Non-Agency RMBS and CMBS
Securities, Available-for-sale [Line Items]
Coupon Interest	5,020	3,307	13,878	10,321
Net Amortization	(52)	748	79	3,179
Interest Income	4,968	4,055	13,957	13,500
CLOs
Securities, Available-for-sale [Line Items]
Coupon Interest	1,523	3,532	5,139	7,978
Net Amortization	(595)	(1,456)	(1,800)	59
Interest Income	928	2,076	3,339	8,037
Other Securities
Securities, Available-for-sale [Line Items]
Coupon Interest	5,473	4,590	15,616	12,296
Net Amortization	(2,377)	(1,813)	(4,525)	(3,796)
Interest Income	3,096	2,777	11,091	8,500
Securities Investment [Member]
Securities, Available-for-sale [Line Items]
Coupon Interest	23,966	26,226	73,860	74,044
Net Amortization	(4,193)	(12,072)	(15,445)	(20,681)
Interest Income	$ 19,773	$ 14,154	$ 58,415	$ 53,363