Shared-Based Compensation - Reconciliation of Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of options, Outstanding, Beginning Balance | shares	897
Number of Options, Granted | shares	126
Number of Options, Exercised | shares	(81)
Number of Options, Forfeited or expired | shares	(2)
Number of Options, Outstanding, Ending Balance | shares	940
Number of Options, Options Exercisable | shares	694
Weighted-Average Exercise Price, Outstanding, Beginning Balance | $ / shares	$ 12.22
Weighted-Average Exercise Price, Granted | $ / shares	24.20
Weighted-Average Exercise Price, Exercised | $ / shares	11.45
Weighted-Average Exercise Price, Forfeited or expired | $ / shares	13.29
Weighted-Average Exercise Price, Outstanding, Ending Balance | $ / shares	13.88
Weighted-Average Exercise Price, Options exercisable | $ / shares	$ 12.11
Weighted-Average Remaining Contractual Term, Outstanding	6 years 6 months
Weighted- Average Remaining Contractual Term, Options exercisable	5 years 4 months 24 days
Aggregate Intrinsic Value, Outstanding | $	$ 10,643
Aggregate Intrinsic Value, Options exercisable | $	$ 9,081