Earnings Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Basic and Diluted Earnings per Share [Line Items]
Net income	$ 325		$ 11,725		$ 24,341		$ 49,614
Weighted-average common shares outstanding (in shares)	25,188,381		25,359,196		25,295,842		25,301,432
Weighted-average common share for EPS calculation (in shares)	25,404,349		25,571,621		25,536,569		25,514,211
Basic earnings per common share (in dollars per share)	$ 0.01		$ 0.46		$ 0.96		$ 1.96
Diluted earnings per common share (in dollars per share)	$ 0.01		$ 0.45		$ 0.95		$ 1.94
Awards excluded from diluted earnings per share calculation(1)	868,020	[1]	646,226	[1]	889,080	[1]	661,826	[1]
Restricted Stock Awards [Member]
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)	114,313		59,849		114,313		59,849
Stock Options [Member]
Basic and Diluted Earnings per Share [Line Items]
Add dilutive effect of share-based awards outstanding (in shares)	101,655		152,576		126,414		152,930

[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.