Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income	$ 88,075	$ 95,916	$ 66,593
Preferred stock dividends	(8,775)	(8,775)	(7,214)
Net income available to common shareholders	79,300	87,141	59,379
Income allocated to participating securities	(726)	(973)	(720)
Net income allocated to common shareholders	$ 78,574	$ 86,168	$ 58,659
Basic weighted average common shares outstanding (in shares)	99,612,473	98,384,443	97,121,497
Dilutive effect of stock options and restricted stock units (in shares)	357,365	0	0
Diluted weighted average common shares outstanding (in shares)	99,969,838	98,384,443	97,121,497
Basic EPS (in dollars per share)	$ 0.79	$ 0.88	$ 0.60
Diluted EPS (in dollars per share)	$ 0.79	$ 0.88	$ 0.60
Employee Non Employee Director Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from computation of earnings per share (in shares)	14,167	962,783	2,096,708
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from computation of earnings per share (in shares)	644,319	758,792