CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net interest income:
Interest income	[1]	$ 1,361,110,000	$ 1,273,316,000	$ 1,138,758,000
Interest expense	[2]	758,814,000	679,108,000	532,748,000
Net interest income		602,296,000	594,208,000	606,010,000
Other-than-temporary impairments:
Total other-than-temporary impairment losses		(801,000)	(2,556,000)	(5,169,000)
Portion of loss recognized in other comprehensive income		(4,052,000)	(19,235,000)	(56,687,000)
Net other-than-temporary credit impairment losses		(4,853,000)	(21,791,000)	(61,856,000)
Other investment gains (losses):
Net unrealized gains (losses) on derivatives		(106,209,000)	(141,162,000)	47,976,000
Realized gains (losses) on terminations of interest rate swaps		(359,726,000)	0	(16,143,000)
Net realized gains (losses) on derivatives		(34,423,000)	18,369,000	(25,645,000)
Net gains (losses) on derivatives		(500,358,000)	(122,793,000)	6,188,000
Net unrealized gains (losses) on financial instruments at fair value		409,634,000	46,632,000	111,410,000
Net realized gains (losses) on sales of investments		20,360,000	(2,743,000)	9,123,000
Gains (losses) on extinguishment of debt		9,318,000	26,376,000	(35,274,000)
Total other gains (losses)		(61,046,000)	(52,528,000)	91,447,000
Other expenses:
Compensation and benefits		48,880,000	35,114,000	30,212,000
General and administrative expenses		26,555,000	22,664,000	17,650,000
Servicing fees		36,290,000	40,773,000	41,690,000
Transaction expenses		10,928,000	9,610,000	21,273,000
Total other expenses		122,653,000	108,161,000	110,825,000
Income (loss) before income taxes		413,744,000	411,728,000	524,776,000
Income taxes		193,000	91,000	108,000
Net income (loss)		413,551,000	411,637,000	524,668,000
Dividends on preferred stock		72,704,000	43,197,000	33,484,000
Net income (loss) available to common shareholders		$ 340,847,000	$ 368,440,000	$ 491,184,000
Net income (loss) per share available to common shareholders:
Basic (usd per share)		$ 1.82	$ 1.97	$ 2.62
Diluted (usd per share)		$ 1.81	$ 1.96	$ 2.61
Weighted average number of common shares outstanding:
Basic (shares)		187,156,990	187,146,170	187,780,355
Diluted (shares)		188,406,444	187,748,862	188,287,320

[1] Includes interest income of consolidated VIEs of $780,746, $904,830 and $914,022 for the years ended December 31, 2019, 2018 and 2017, respectively. See Note 8 to consolidated financial statements for further discussion.

[2] Includes interest expense of consolidated VIEs of $337,387, $395,255 and $390,858 for the years ended December 31, 2019, 2018 and 2017, respectively. See Note 8 to consolidated financial statements for further discussion.