Consolidated Statements of Shareholders' Equity Statement - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Preferred Stock	Preferred Stock Including Additional Paid in Capital	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at Dec. 31, 2017	$ 557,058		$ 141,294	$ 558	$ 775,873	$ (8,697)	$ (351,970)
Balance, Preferred shares outstanding at Dec. 31, 2017	5,888,680	5,888,680
Balance, Common shares outstanding at Dec. 31, 2017	55,831,549			55,831,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues		52,979		3,028,983
Stock Issued During Period, Shares, Restricted Stock Award, Gross				213,157
Shares Paid for Tax Withholding for Share Based Compensation				57,135
Stock issuance	$ 20,571		1,290	$ 31	19,250
Restricted stock granted, net of amortization	930			2	928
Adjustments for tax withholding on share-based compensation	(364)			(1)	(363)
Stock issuance costs	(68)		(10)		(58)
Net income	85,545						85,545
Dividends on preferred stock	(8,838)						(8,838)
Dividends on common stock	(30,945)						(30,945)
Other comprehensive loss	(77,136)					(77,136)
Balance at Sep. 30, 2018	$ 546,753		$ 142,574	$ 590	$ 795,630	$ (85,833)	$ (306,208)
Balance, Preferred shares outstanding at Sep. 30, 2018	5,941,659	5,941,659
Balance, Common shares outstanding at Sep. 30, 2018	59,016,554			59,016,554