Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net earnings (loss)	$ 6,181	$ (4,092)	$ 41,188	$ 46,353
Basic weighted average shares	53,155,000	53,060,000	53,111,000	53,044,000
Basic earnings (loss) per common share	$ 0.12	$ (0.08)	$ 0.78	$ 0.87
Effect of dilutive stock options	299,000	273,000	281,000	313,000
Diluted weighted average shares		53,333,000		53,357,000
Diluted earnings (loss) per common share	$ 0.12	$ (0.08)	$ 0.77	$ 0.87
Earnings Per Share (Details) [Abstract]
Number of anti-dilutive stock awards	3,999,515	2,676,685	3,431,945