Earnings Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net income (loss)	$ 5,047	$ 4,341	$ (2,324)	$ (2,693)	$ (40,929)	$ 3,936	$ 3,655	$ 275	$ 4,370	$ (33,063)	$ 43,736
Denominator:
Denominator for basic earnings per share—weighted-average shares outstanding (in shares)									53,607	52,791	52,096
Effect of dilutive securities:
Employee stock options and restricted common shares (in shares)									728	0	924
Contingently issuable shares (in shares)									125	0	84
Denominator for dilutive earnings per share (in shares)									54,460	52,791	53,104
Basic earnings (loss) per share (in USD per share)	$ 0.09	$ 0.08	$ (0.04)	$ (0.05)	$ (0.77)	$ 0.07	$ 0.07	$ 0.01	$ 0.08	$ (0.63)	$ 0.84
Diluted earnings (loss) per share (in USD per share)	$ 0.09	$ 0.08	$ (0.04)	$ (0.05)	$ (0.77)	$ 0.07	$ 0.07	$ 0.01	$ 0.08	$ (0.63)	$ 0.82