Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Interest income	$ 86,695	$ 60,051	$ 96,468
Interest expense	(43,612)	(5,671)	(32,615)
Net interest income	43,083	54,380	63,853
Realized (loss) gain on sale of investments, net	(89,067)	6,705	308,084
Unrealized (loss) gain on investments, net	(213,022)	(14,814)	20
Gain (loss) on derivative instruments, net	436,007	81,417	(172,290)
Total other gains, net	133,918	73,308	135,814
Noninterest Expense [Abstract]
Compensation and benefits	(16,808)	(12,757)	(11,743)
Other general and administrative	(15,545)	(11,328)	(9,337)
Other operating expenses	(1,487)	(1,342)	(1,057)
Total operating expenses	(33,840)	(25,427)	(22,137)
Net income	143,161	102,261	177,530
Preferred stock dividends	(7,694)	(8,329)	(13,599)
Preferred stock redemption charge	0	(2,987)	(3,914)
Net (loss) income to common stockholders	135,467	90,945	160,017
Other comprehensive income:
Unrealized (loss) gain on available-for-sale investments, net	(202,063)	(66,827)	214,539
Reclassification adjustment for realized loss (gain) on available-for-sale investments, net	13,988	(6,705)	(308,084)
Total other comprehensive loss	(188,075)	(73,532)	(93,545)
Comprehensive (loss) income to common shareholders	$ (52,608)	$ 17,413	$ 66,472
Weighted average common shares-basic (in shares)	42,491,433	32,596,272	23,106,200
Weighted average common shares-diluted (in shares)	42,743,037	32,761,331	23,106,200
Net income (loss) per common share-basic (in dollars per share)	$ 3.19	$ 2.79	$ 6.93
Net income (loss) per common share-diluted (in dollars per share)	$ 3.17	$ 2.78	$ 6.93