Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 18,906	$ 18,808	$ 69,644	$ 72,657
Preferred stock dividends	(2,194)	(2,194)	(6,582)	(6,582)
Net income available to common shareholders	16,712	16,614	63,062	66,075
Income allocated to participating securities	(173)	(187)	(578)	(742)
Net income allocated to common shareholders	$ 16,539	$ 16,427	$ 62,484	$ 65,333
Basic weighted average common shares outstanding	99,700,759	98,453,265	99,540,721	98,279,671
Weighted Average Number Diluted Shares Outstanding Adjustment	366,400		366,400
Diluted weighted average common shares outstanding	100,067,159	98,453,265	99,907,121	98,279,671
Basic EPS	$ 0.17	$ 0.17	$ 0.63	$ 0.66
Diluted EPS	$ 0.17	$ 0.17	$ 0.63	$ 0.66
Options
Antidilutive securities excluded from computation of earnings per share
Stock options excluded from computation of earnings per share (in shares)	12,000	988,050	14,889	1,016,451
Restricted stock units (RSUs)
Antidilutive securities excluded from computation of earnings per share
Restricted stock units excluded from the computation of earning per share (in shares)	760,979	788,874	607,856	751,149