CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - 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, 2018	$ 1,059,063	$ 250,946	$ 853	$ 1,174,880	$ (346,570)	$ (21,046)
Net income (loss)	(68,010)				(68,010)
Change in unrealized gain on mortgage securities, net	89,334					89,334
Amounts related to cash flow hedges, net	(42,569)					(42,569)
Cash dividends:
Common	(28,557)				(28,557)
Preferred	(14,525)				(14,525)
Issuance of common stock	75,102		90	75,012
Other additions to capital	1,918		3	1,915
Ending Balance at Sep. 30, 2019	1,071,756	250,946	946	1,251,807	(457,662)	25,719
Beginning Balance at Jun. 30, 2019	1,022,388	250,946	855	1,176,529	(444,703)	38,761
Net income (loss)	3,196				3,196
Change in unrealized gain on mortgage securities, net	(2,692)					(2,692)
Amounts related to cash flow hedges, net	(10,350)					(10,350)
Cash dividends:
Common	(11,313)				(11,313)
Preferred	(4,842)				(4,842)
Issuance of common stock	75,102		90	75,012
Other additions to capital	267		1	266
Ending Balance at Sep. 30, 2019	1,071,756	250,946	946	1,251,807	(457,662)	25,719
Beginning Balance at Dec. 31, 2019	1,073,733	250,946	946	1,252,481	(444,039)	13,399
Net income (loss)	(152,867)				(152,867)
Change in unrealized gain on mortgage securities, net	53,190					53,190
Amounts related to cash flow hedges, net	(17,335)					(17,335)
Cash dividends:
Common	(43,577)				(43,577)
Preferred	(14,525)				(14,525)
Issuance of common stock	12,857		16	12,841
Other additions to capital	2,353		3	2,350
Ending Balance at Sep. 30, 2020	913,829	250,946	965	1,267,672	(655,008)	49,254
Beginning Balance at Jun. 30, 2020	912,889	250,946	964	1,266,976	(664,749)	58,752
Net income (loss)	29,082				29,082
Change in unrealized gain on mortgage securities, net	(12,563)					(12,563)
Amounts related to cash flow hedges, net	3,065					3,065
Cash dividends:
Common	(14,499)				(14,499)
Preferred	(4,842)				(4,842)
Other additions to capital	697		1	696
Ending Balance at Sep. 30, 2020	$ 913,829	$ 250,946	$ 965	$ 1,267,672	$ (655,008)	$ 49,254