Investment in Securities (Proceeds, Realized Gains (Losses) on Sales) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Securities, Available-for-sale [Line Items]
Available-for-sale securities Realizes Losses - adjustments to cost basis of certain securities	$ (9,700,000)	$ (5,700,000)
Agency RMBS
Securities, Available-for-sale [Line Items]
Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale	236,602,000	205,504,000
Debt Securities, Available-for-Sale, Realized Gain	1,077,000	796,000
Debt Securities, Available-for-Sale, Realized Loss	(13,231,000)	(26,336,000)
Debt Securities, Available-for-Sale, Realized Gain (Loss)	(12,154,000)	(25,540,000)
Non-Agency RMBS and CMBS
Securities, Available-for-sale [Line Items]
Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale	112,793,000	27,188,000
Debt Securities, Available-for-Sale, Realized Gain	6,814,000	1,084,000
Debt Securities, Available-for-Sale, Realized Loss	(865,000)	(15,000)
Debt Securities, Available-for-Sale, Realized Gain (Loss)	5,949,000	1,069,000
CLOs
Securities, Available-for-sale [Line Items]
Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale	2,312,000	0
Debt Securities, Available-for-Sale, Realized Gain	388,000	89,000
Debt Securities, Available-for-Sale, Realized Loss	(122,000)	0
Debt Securities, Available-for-Sale, Realized Gain (Loss)	266,000	89,000
Other Securities
Securities, Available-for-sale [Line Items]
Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale	55,270,000	274,056,000
Debt Securities, Available-for-Sale, Realized Gain	1,528,000	320,000
Debt Securities, Available-for-Sale, Realized Loss	(622,000)	(1,749,000)
Debt Securities, Available-for-Sale, Realized Gain (Loss)	906,000	(1,429,000)
Securities Investment [Member]
Securities, Available-for-sale [Line Items]
Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale	406,977,000	506,748,000
Debt Securities, Available-for-Sale, Realized Gain	9,807,000	2,289,000
Debt Securities, Available-for-Sale, Realized Loss	(14,840,000)	(28,100,000)
Debt Securities, Available-for-Sale, Realized Gain (Loss)	$ (5,033,000)	$ (25,811,000)