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
Basic and Diluted Earnings per Share [Line Items]
Net income		$ 19,534	$ 325	$ 58,231	$ 24,341
Weighted-average common shares outstanding (in shares)		25,067,080	25,188,381	25,027,382	25,295,842
Weighted-average common share for EPS calculation (in shares)		25,379,348	25,404,349	25,171,881	25,536,569
Basic earnings per common share (in dollars per share)		$ 0.78	$ 0.01	$ 2.33	$ 0.96
Diluted earnings per common share (in dollars per share)		$ 0.77	$ 0.01	$ 2.31	$ 0.95
Awards excluded from diluted earnings per share calculation (in shares)	[1]	260,035	868,020	410,425	889,080
Restricted Stock Awards [Member]
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)		125,135	114,313	125,135	114,313
Stock Options [Member]
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)		187,133	101,655	19,364	126,414

[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.