Stock-based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Beginning Balance	480,736
Granted, Shares	84,672
Exercised, Shares	(45,289)	(67,029)	(227,410)
Forfeited, Shares	(13,035)
Shares, Ending Balance	507,084	480,736
Vested or expected to vest, Shares	506,473
Exercisable, Shares	381,257
Weighted Average Exercise Price, Beginning Balance	$ 34.35
Granted, Weighted Average Exercise Price	41.21
Exercised, Weighted Average Exercise Price	17.16
Forfeited, Weighted Average Exercise Price	52.25
Weighted Average Exercise Price, Ending Balance	36.57	$ 34.35
Vested or expected to vest, Weighted Average Exercise Price	36.56
Exercisable, Weighted Average Exercise Price	$ 32.59
Weighted Average Remaining Contractual Term, Ending Balance	4 years 6 months 11 days
Vested or expected to vest, Weighted Average Remaining Contractual Term	4 years 6 months 7 days
Exercisable, Weighted Average Remaining Contractual Term	3 years 1 month 21 days
Aggregate Intrinsic Value, Ending Balance	$ 6,654
Vested or expected to vest, Aggregate Intrinsic Value	6,649
Exercisable, Aggregate Intrinsic Value	$ 6,518