Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest income	$ 20,088,000	$ 44,502,000	$ 79,764,000	$ 128,207,000
Interest expense	3,375,000	31,256,000	30,327,000	88,345,000
Net interest income	16,713,000	13,246,000	49,437,000	39,862,000
Gain (loss) on derivative instruments, net	(7,974,000)	50,709,000	196,156,000	229,941,000
Gain (loss) on sale of investments, net	20,846,000	4,605,000	298,728,000	(5,755,000)
Fair value adjustments, net	194,000	(13,000)	154,000	(42,000)
Other operating (expense) income, net	(207,000)	25,000	(852,000)	50,000
General and administrative expenses:
Compensation and benefits	(2,402,000)	(1,786,000)	(7,301,000)	(5,430,000)
Other general and administrative	(2,393,000)	(1,972,000)	(6,926,000)	(6,547,000)
Net income (loss)	40,725,000	(36,604,000)	137,084,000	(207,803,000)
Preferred stock dividends	(3,252,000)	(3,341,000)	(10,346,000)	(9,606,000)
Preferred stock redemption charge	0	0	3,914,000	0
Net income (loss) to common shareholders	37,473,000	(39,945,000)	122,824,000	(217,409,000)
Other comprehensive income:
Unrealized gain on available-for-sale investments, net	27,844,000	59,800,000	213,651,000	247,199,000
Reclassification adjustment for (gain) loss on sale of investments, net	(20,846,000)	(4,605,000)	(298,728,000)	5,755,000
Reclassification adjustment for de-designated cash flow hedges	0	0	0	(165,000)
Total other comprehensive income (loss)	6,998,000	55,195,000	(85,077,000)	252,789,000
Comprehensive income to common shareholders	$ 44,471,000	$ 15,250,000	$ 37,747,000	$ 35,380,000
Net income (loss) per common share-basic and diluted	$ 1.62	$ (1.65)	$ 5.33	$ (9.12)
Weighted average common shares-basic and diluted	23,141	24,174	23,054	23,847