Stockholders' Equity - Schedule of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding at December 31, 2014	1,954
Number of Shares, Granted	450
Number of Shares, Exercised	(49)
Number of Shares, Forfeited	(111)
Number of Shares, Outstanding at September 30, 2015	2,244
Number of Shares, Exercisable at September 30, 2015	1,132
Number of Shares, Vested and expected to vest at September 30, 2015	2,114
Weighted - Average Exercise Price Per Share, Outstanding, Beginning balance | $ / shares	$ 33.81
Weighted - Average Exercise Price Per Share, Granted | $ / shares	33.74
Weighted - Average Exercise Price Per Share, Exercised | $ / shares	29.38
Weighted - Average Exercise Price Per Share, Forfeited | $ / shares	36.23
Weighted - Average Exercise Price Per Share, Outstanding, Ending balance | $ / shares	33.77
Weighted - Average Exercise Price Per Share, Exercisable at September 30, 2015 | $ / shares	32.14
Weighted Average Exercise Price Per Share, Vested and expected to vest at September 30, 2015 | $ / shares	$ 33.67
Weighted - Average Remaining Contractual Term, Outstanding at September 30, 2015	6 years 11 months 1 day
Weighted - Average Remaining Contractual Term, Exercisable at September 30, 2015	5 years 22 days
Weighted - Average Remaining Contractual Term, Vested and expected to vest at September 30, 2015	6 years 9 months 11 days
Aggregate Intrinsic Value, Outstanding at September 30, 2015 | $	$ 2,000
Aggregate Intrinsic Value, Exercisable at September 30, 2015 | $	1,817
Aggregate Intrinsic Value, Vested and expected to vest at September 30, 2015 | $	$ 1,989