Net Income per Share - Additional Information (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
Net Income per Share
Net income	$ 812	$ 7,808	$ 5,865	$ 14,934
Basic weighted average shares of common stock	54,179,369	54,179,369	54,179,369	54,057,822
Dilutive effect of stock options		376,848		571,690
Diluted weighted average shares of common stock	54,179,369	54,556,217	54,179,369	54,629,512
Basic:
Net income (loss) per common share: Basic	$ 0.01	$ 0.14	$ 0.11	$ 0.28
Diluted:
Net income (loss) per common share: Diluted	$ 0.01	$ 0.14	$ 0.11	$ 0.27