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, 2017	$ 1,238,876	$ 250,946	$ 957	$ 1,271,425	$ (346,570)	$ 62,118
Net income (loss)	41,088				41,088
Change in unrealized gain on mortgage securities, net	(87,336)					(87,336)
Amounts related to cash flow hedges, net	20,609					20,609
Cash dividends:
Common	(37,706)			(11,143)	(26,563)
Preferred	(14,525)				(14,525)
Common stock repurchases	(41,313)		(48)	(41,265)
Other additions to capital	1,400		2	1,398
Ending Balance at Sep. 30, 2018	1,121,093	250,946	911	1,220,415	(346,570)	(4,609)
Beginning Balance at Jun. 30, 2018	1,168,856	250,946	924	1,237,812	(346,570)	25,744
Net income (loss)	8,680				8,680
Change in unrealized gain on mortgage securities, net	(26,771)					(26,771)
Amounts related to cash flow hedges, net	(3,582)					(3,582)
Cash dividends:
Common	(10,041)			(6,203)	(3,838)
Preferred	(4,842)				(4,842)
Common stock repurchases	(11,841)		(14)	(11,827)
Other additions to capital	634		1	633
Ending Balance at Sep. 30, 2018	1,121,093	250,946	911	1,220,415	(346,570)	(4,609)
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