Net Income (Loss) per Share of Common Stock (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerators for earnings per share:
Net income (loss) that is available to common shareholders	$ 13,758	$ 4,749	$ (14,794)	$ 19,174
Denominator for basic earnings per share:
Weighted average shares outstanding	21,799,782	21,492,625	21,667,408	21,300,212
Denominator for diluted earnings per share:
Effect of stock options and restricted stock units	440,531	730,697	0	629,200
Adjusted weighted average shares and assumed conversions	22,240,313	22,223,322	21,667,408	21,929,412
Basic earnings (loss) per share	$ 0.63	$ 0.22	$ (0.68)	$ 0.90
Diluted earnings (loss) per share	$ 0.62	$ 0.21	$ (0.68)	$ 0.87
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	0	458,658	0
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	192,090	319,288	151,732	280,859