Earnings per Common Share - Schedule of Weighted Average Shares Outstanding Used in Calculation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings per Common Share and Dividends Declared per Common Share
Net income available to common shareholders	$ 11,193	$ 10,269	$ 29,296	$ 26,166
Dividends and undistributed earnings allocated to participating securities	(109)	(116)	(296)	(300)
Earnings allocated to common shares	$ 11,084	$ 10,153	$ 29,000	$ 25,866
Weighted average common shares - issued	41,783,604	41,434,195	41,713,831	41,334,632
Average unvested restricted share awards	(406,406)	(462,927)	(421,174)	(472,885)
Weighted average common shares outstanding - basic	41,377,198	40,971,268	41,292,657	40,861,747
Effect of dilutive stock options and awards outstanding	404,218	220,779	400,977	180,676
Weighted average common shares outstanding - diluted	41,781,416	41,192,047	41,693,634	41,042,423
Weighted average antidilutive securities outstanding	41,101	118,596	27,336	158,154
Basic earnings per common share	$ 0.27	$ 0.25	$ 0.70	$ 0.63
Diluted earnings per common share	0.27	0.25	0.70	0.63
Dividends declared per share	$ 0.055	$ 0.050	$ 0.155	$ 0.140