Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net income	$ 18,336	$ 31,431	$ 36,901	$ 50,738
Preferred stock dividends	(2,194)	(2,194)	(4,388)	(4,388)
Net income available to common shareholders	16,142	29,237	32,513	46,350
Income allocated to participating securities	(160)	(295)	(296)	(394)
Net income allocated to common shareholders	$ 15,982	$ 28,942	$ 32,217	$ 45,956
Basic weighted average common shares outstanding	100,380,937	99,664,442	100,374,934	99,459,376
Dilutive effect of stock options and restricted stock units (in shares)	0	0	0	0
Diluted weighted average common shares outstanding	100,380,937	99,664,442	100,374,934	99,459,376
Basic EPS (in dollars per share)	$ 0.16	$ 0.29	$ 0.32	$ 0.46
Diluted EPS (in dollars per share)	$ 0.16	$ 0.29	$ 0.32	$ 0.46
Options
Antidilutive securities excluded from computation of earnings per share
Stock options excluded from computation of earnings per share (in shares)	6,000	12,000	6,495	16,334
Restricted stock units (RSUs)
Antidilutive securities excluded from computation of earnings per share
Stock options excluded from computation of earnings per share (in shares)	744,923	1,029,336	746,027	896,425