Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net Income (Loss) Attributable to Parent	$ 28,673	$ 30,759	$ 9,613	$ (8,560)	$ 16,976	$ 15,282	$ 13,641	$ (20,553)	$ 60,485	$ 25,346	$ (36,423)
Weighted average common stock outstanding, basic (in shares)									39,337,000	39,096,000	38,803,000
Dilutive effect of stock options and restricted stock units1									531,000	699,000	0
Weighted average common stock outstanding, diluted (in shares)									39,868,000	39,795,000	38,803,000
Basic (in dollars per share)	$ 0.73	$ 0.78	$ 0.24	$ (0.22)	$ 0.43	$ 0.39	$ 0.35	$ (0.53)	$ 1.54	$ 0.65	$ (0.94)
Diluted (in dollars per share)	$ 0.72	$ 0.77	$ 0.24	$ (0.22)	$ 0.43	$ 0.38	$ 0.34	$ (0.53)	$ 1.52	$ 0.64	$ (0.94)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount											862,000