Earnings Per Share - Schedule of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		2,700
Numerator:
Net (loss) income	$ (1,684)	$ 5,678
Denominator:
Weighted-average shares outstanding – basic (in shares)	53,716	54,056
Effect of dilutive securities:
Employee and director stock options and restricted common shares (in shares)	0	548
Contingently issuable shares (in shares)	0	(125)
Weighted-average shares outstanding – diluted (in shares)	53,716	54,729
Basic earnings per share (in dollars per share)	$ (0.03)	$ 0.11
Diluted earnings per share (in dollars per share)	$ (0.03)	$ 0.10