Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share
Net (loss) income for basic and diluted (loss) earnings per share	$ (10,210)	$ 12,926	$ 6,523	$ 26,546
Shares of common stock and common stock equivalents:
Average common shares used in basic computation	34,076	35,720	34,172	35,900
Effect of dilutive securities (in shares)		921	1,157	1,033
Average common shares used in diluted computation	34,076	36,641	35,329	36,933
(Loss) earnings per share:
Basic (in dollars per share)	$ (0.30)	$ 0.36	$ 0.19	$ 0.74
Diluted (in dollars per share)	$ (0.30)	$ 0.35	$ 0.18	$ 0.72
Anti-dilutive equity awards not included in the detailed earnings per share computation
Equity awards not included in the diluted earnings per share computation	3,294	83	7	220