Net Income (Loss) per Share of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerators for earnings per share:
Net income (loss) that is available to common shareholders	$ 14,394	$ (25,168)	$ 17,506	$ (28,552)
Denominator for basic earnings per share:
Weighted average shares outstanding	21,775,280	21,672,844	21,826,566	21,600,125
Denominator for diluted earnings per share:
Effect of stock options and restricted stock units	458,746	0	478,309	0
Adjusted weighted average shares and assumed conversions	22,234,026	21,672,844	22,304,875	21,600,125
Basic earnings (loss) per share	$ 0.66	$ (1.16)	$ 0.80	$ (1.32)
Diluted earnings (loss) per share	$ 0.65	$ (1.16)	$ 0.78	$ (1.32)
Net loss position (excluded from denominator)
Shares excluded from diluted earnings (loss) per share due to:
Antidilutive securities excluded from diluted earnings per share	0	490,706	0	465,577
Inclusion would have been anti-dilutive (excluded from calculation)
Shares excluded from diluted earnings (loss) per share due to:
Antidilutive securities excluded from diluted earnings per share	87,164	182,850	84,046	130,165