Summary of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Number of options
Number of options, Outstanding at beginning of year | shares	35,799
Number of options, Granted | shares	6,939
Number of options, Exercised | shares	(7,705)
Number of options, Forfeited | shares	(1,831)
Number of options, Expired | shares	(126)
Number of options, Outstanding at end of year | shares	33,076
Number of options, Vested or expected to vest at end of year | shares	32,502
Number of options , Exercisable at end of year | shares	18,707
Stock options grant weighted-average exercise price
Weighted-average exercise price, Outstanding at beginning of year | $ / shares	$ 34.16
Weighted-average exercise price, Granted | $ / shares	39.70
Weighted-average exercise price, Exercised | $ / shares	31.50
Weighted-average exercise price, Forfeited | $ / shares	38.14
Weighted-average exercise price, Expired | $ / shares	32.87
Weighted Average Exercise Price Outstanding at end of year | $ / shares	35.73
Weighted Average Exercise Price Vested or expected to vest at end of year | $ / shares	35.67
Weighted Average Exercise Price Exercisable at end of year | $ / shares	$ 33.71
Stock options grant Weighted-average remaining contractual life
Weighted average remaining contractual life, Outstanding at end of year	6 years 2 months 12 days
Weighted average remaining contractual life, Vested or expected to vest at end of year	6 years 2 months 12 days
Weighted average remaining contractual life, Exercisable at end of year	4 years 8 months 12 days
Stock options grant aggregate intrinsic value
Aggregate intrinsic value, outstanding, ending balance | $	$ 284,821
Aggregate intrinsic value,Vested or expected to vest at end of year | $	281,976
Aggregate intrinsic value, Exercisable at end of year | $	$ 198,873