Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Basic and Diluted Earnings per Share [Line Items]
Net income		$ 22,427	$ 23,679
Weighted-average common shares outstanding (in shares)		25,209,888	24,990,470
Weighted-average common share for EPS calculation (in shares)		25,596,437	25,104,783
Basic earnings per common share (in dollars per share)		$ 0.89	$ 0.95
Diluted earnings per common share (in dollars per share)		$ 0.88	$ 0.94
Awards excluded from diluted earnings per share calculation (in shares)	[1]	180,912	697,950
Restricted Stock Awards [Member]
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)		154,742	114,313
Stock Options [Member]
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)		231,807	0

[1] Outstanding awards that are not "in-the-money" are excluded from the diluted earnings per share calculation because the effect of including them would have been anti-dilutive.