Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Common Share
Net income (loss)	$ 11,407	$ (8,986)	$ 31,517	$ (3,516)
Basic:
Weighted average shares outstanding	37,056	36,657	37,023	36,659
Earnings Per Share, Basic	$ 0.31	$ (0.25)	$ 0.85	$ (0.10)
Diluted:
Effect of dilutive securities - options	276		250
Weighted Average Number of Shares Outstanding, Diluted, Total	37,332	36,657	37,273	36,659
Earnings Per Share, Diluted	$ 0.31	$ (0.25)	$ 0.85	$ (0.10)