Stock-based Compensation - Schedule of Stock Options Outstanding and Exercisable (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares, Options outstanding, beginning balance | shares	315
Shares outstanding, Options exercised | shares	(140)
Shares, Options outstanding, ending balance | shares	175
Shares outstanding, Options vested and expected to vest, ending balance | shares	175
Shares outstanding, Options exercisable, ending balance | shares	175
Weighted average exercise price, Options outstanding, beginning balance | $ / shares	$ 13.86
Weighted average exercise price, Options exercised | $ / shares	12.22
Weighted average exercise price, Options outstanding, ending balance | $ / shares	15.18
Weighted average exercise price, Options vested and expected to vest, ending balance | $ / shares	15.18
Weighted average exercise price, Options exercisable, ending balance | $ / shares	$ 15.18
Weighted average remaining contractual term (years), Options outstanding	1 year 3 months 26 days
Weighted average remaining contractual term (years), Options vested and expected to vest	1 year 3 months 26 days
Weighted average remaining contractual term (years), Options exercisable	1 year 3 months 26 days
Aggregate intrinsic value, Options outstanding | $	$ 4,812
Aggregate intrinsic value, Options vested and expected to vest | $	4,812
Aggregate intrinsic value, Options exercisable | $	$ 4,812