Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 31,431	$ 22,300	$ 50,738	$ 53,849
Preferred stock dividends	(2,194)	(2,194)	(4,388)	(4,388)
Net income available to common shareholders	29,237	20,106	46,350	49,461
Income allocated to participating securities	(295)	(232)	(394)	(552)
Net income allocated to common shareholders	$ 28,942	$ 19,874	$ 45,956	$ 48,909
Basic weighted average common shares outstanding	99,664,442	98,275,886	99,459,376	98,191,434
Diluted weighted average common shares outstanding	99,664,442	98,275,886	99,459,376	98,191,434
Basic EPS	$ 0.29	$ 0.20	$ 0.46	$ 0.50
Diluted EPS	$ 0.29	$ 0.20	$ 0.46	$ 0.50
Options
Antidilutive securities excluded from computation of earnings per share
Stock options excluded from computation of earnings per share (in shares)	12,000	1,011,219	16,334	1,030,651
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)	1,029,336	803,318	896,425	731,973