CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2017	$ 1,238,876	$ 250,946	$ 957	$ 1,271,425	$ (346,570)	$ 62,118
Net income (loss)	50,072				50,072
Change in unrealized gain on mortgage securities, net	(72,490)					(72,490)
Amounts related to cash flow hedges, net	(10,674)					(10,674)
Cash dividends:
Common	(44,463)			(13,759)	(30,704)
Preferred	(19,368)				(19,368)
Common stock repurchases	(84,594)		(107)	(84,487)
Other additions to capital	1,704		3	1,701
Ending Balance at Dec. 31, 2018	1,059,063	250,946	853	1,174,880	(346,570)	(21,046)
Net income (loss)	(35,338)				(35,338)
Change in unrealized gain on mortgage securities, net	72,513					72,513
Amounts related to cash flow hedges, net	(38,068)					(38,068)
Cash dividends:
Common	(42,763)				(42,763)
Preferred	(19,368)				(19,368)
Issuance of common stock	75,102		90	75,012
Other additions to capital	2,592		3	2,589
Ending Balance at Dec. 31, 2019	1,073,733	250,946	946	1,252,481	(444,039)	13,399
Net income (loss)	(129,573)				(129,573)
Change in unrealized gain on mortgage securities, net	39,284					39,284
Amounts related to cash flow hedges, net	(11,799)					(11,799)
Cash dividends:
Common	(58,091)				(58,091)
Preferred	(19,368)				(19,368)
Issuance of common stock	12,857		16	12,841
Other additions to capital	3,120		3	3,117
Ending Balance at Dec. 31, 2020	$ 910,163	$ 250,946	$ 965	$ 1,268,439	$ (651,071)	$ 40,884