Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net (loss) earnings	$ (105,195)	$ (953,520)	$ 96,422
Basic weighted average shares	53,121,000	53,050,000	52,850,000
Effect of dilutive stock options	0	0	276,000
Diluted weighted average shares	53,121,000	53,050,000	53,126,000
Basic (loss) earnings per common share	$ (1.98)	$ (17.97)	$ 1.82
Diluted (loss) earnings per common share	$ (1.98)	$ (17.97)	$ 1.81
Number of anti-dilutive stock options	3,072,181	2,585,711	2,496,147