Stock Options Outstanding and Exercisable Price Range Status (Detail)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Shares | shares	3,492,000
Options Exercisable, Shares | shares	2,110,000
Exercise Price Range 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Range, minimum	$ 25.73
Exercise Price Range, maximum	$ 31.13
Options Outstanding, Shares | shares	729,000
Options Outstanding, Weighted-Average Exercise Price	$ 28.81
Options Outstanding, Weighted-Average Remaining Contractual Term (Years)	4 years 7 months 6 days
Options Exercisable, Shares | shares	393,000
Options Exercisable, Weighted-Average Exercise Price	$ 27.76
Exercise Price Range 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Range, minimum	31.54
Exercise Price Range, maximum	$ 36.29
Options Outstanding, Shares | shares	717,000
Options Outstanding, Weighted-Average Exercise Price	$ 34.46
Options Outstanding, Weighted-Average Remaining Contractual Term (Years)	6 years 2 months 12 days
Options Exercisable, Shares | shares	336,000
Options Exercisable, Weighted-Average Exercise Price	$ 34.80
Exercise Price Range 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Range, minimum	36.43
Exercise Price Range, maximum	$ 37.95
Options Outstanding, Shares | shares	716,000
Options Outstanding, Weighted-Average Exercise Price	$ 37.06
Options Outstanding, Weighted-Average Remaining Contractual Term (Years)	7 years 2 months 12 days
Options Exercisable, Shares | shares	262,000
Options Exercisable, Weighted-Average Exercise Price	$ 37.40
Exercise Price Range 4
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Range, minimum	38.03
Exercise Price Range, maximum	$ 43.13
Options Outstanding, Shares | shares	710,000
Options Outstanding, Weighted-Average Exercise Price	$ 40.57
Options Outstanding, Weighted-Average Remaining Contractual Term (Years)	5 years 3 months 18 days
Options Exercisable, Shares | shares	501,000
Options Exercisable, Weighted-Average Exercise Price	$ 40.34
Exercise Price Range 5
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Range, minimum	43.27
Exercise Price Range, maximum	$ 70.55
Options Outstanding, Shares | shares	620,000
Options Outstanding, Weighted-Average Exercise Price	$ 56.07
Options Outstanding, Weighted-Average Remaining Contractual Term (Years)	2 years 9 months 18 days
Options Exercisable, Shares | shares	618,000
Options Exercisable, Weighted-Average Exercise Price	$ 56.11