Investment in Securities (Proceeds, Realized Gains (Losses) on Sales) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Securities, Available-for-sale [Line Items]
Proceeds	$ 405,531,000	$ 328,763,000	$ 1,091,040,000	$ 1,116,415,000
Available-for-sale Securities, Gross Realized Gains	6,898,000	10,024,000	20,354,000	24,154,000
Available-for-sale Securities, Gross Realized Losses	35,716,000	3,254,000	70,904,000	12,870,000
Available-for-sale Securities, Gross Realized Gain (Loss)	(28,818,000)	6,770,000	(50,550,000)	11,284,000
Available-for-sale securities Realizes Losses - adjustments to cost basis of certain securities	(2,000,000.0)	(300,000)	(4,500,000)	(1,500,000)
Agency RMBS
Securities, Available-for-sale [Line Items]
Proceeds	311,908,000	128,510,000	878,629,000	620,728,000
Available-for-sale Securities, Gross Realized Gains	728,000	831,000	1,923,000	4,171,000
Available-for-sale Securities, Gross Realized Losses	34,921,000	1,860,000	68,939,000	9,114,000
Available-for-sale Securities, Gross Realized Gain (Loss)	(34,193,000)	(1,029,000)	(67,016,000)	(4,943,000)
Non-Agency RMBS and CMBS
Securities, Available-for-sale [Line Items]
Proceeds	13,121,000	55,122,000	20,715,000	196,874,000
Available-for-sale Securities, Gross Realized Gains	2,210,000	3,887,000	6,546,000	13,396,000
Available-for-sale Securities, Gross Realized Losses	372,000	1,081,000	398,000	2,598,000
Available-for-sale Securities, Gross Realized Gain (Loss)	1,838,000	2,806,000	6,148,000	10,798,000
CLOs
Securities, Available-for-sale [Line Items]
Proceeds	992,000	0	18,259,000	129,001,000
Available-for-sale Securities, Gross Realized Gains	3,324,000	2,846,000	7,584,000	3,882,000
Available-for-sale Securities, Gross Realized Losses	57,000	0	747,000	973,000
Available-for-sale Securities, Gross Realized Gain (Loss)	3,267,000	2,846,000	6,837,000	2,909,000
Other Securities
Securities, Available-for-sale [Line Items]
Proceeds	79,510,000	145,131,000	173,437,000	169,812,000
Available-for-sale Securities, Gross Realized Gains	636,000	2,460,000	4,301,000	2,705,000
Available-for-sale Securities, Gross Realized Losses	366,000	313,000	820,000	185,000
Available-for-sale Securities, Gross Realized Gain (Loss)	$ 270,000	$ 2,147,000	$ 3,481,000	$ 2,520,000