Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Balance as of January 1	14,435	15,427	15,236
Options, Granted	7,572	4,113	4,016
Options, Exercised	(4,201)	(3,804)	(2,730)
Options, Cancelled	(751)	(1,301)	(1,095)
Options, Balance as of December 31	17,055	14,435	15,427
Weighted Average Exercise Price, January 1	$ 49.33	$ 36.03	$ 25.24
Options, Exercisable as of December 31, 2015	4,880
Weighted Average Exercise Price, Granted	$ 94.13	78.70	65.29
Options, Vested and expected to vest after December 31, 2015	15,980
Weighted Average Exercise Price, Exercised	$ 34.57	25.66	18.10
Weighted Average Exercise Price, Cancelled	74.06	53.69	37.87
Weighted Average Exercise Price, December 31	71.77	$ 49.33	$ 36.03
Weighted Average Exercise Price, Exercisable as of December 31, 2015	42.32
Weighted Average Exercise Price, Vested and expected to vest after December 31, 2015	$ 70.70
Remaining Contractual Life (In years), Balance as of December 31, 2015	4 years 10 months 24 days
Remaining Contractual Life (In years), Exercisable as of December 31, 2015	3 years 2 months 12 days
Remaining Contractual Life (In years), Vested and expected to vest after December 31, 2015	4 years 10 months 24 days
Aggregate intrinsic value, Balance as of December 31, 2015	$ 896,377
Aggregate intrinsic value, Exercisable as of December 31, 2015	400,120
Aggregate intrinsic value, Vested and expected to vest after December 31, 2015	$ 856,574