Additional Information about Stock options Outstanding (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding at end of year	6,006,585
Options Outstanding, Avg. Life in Years	4 years 4 months 24 days
Options Outstanding, Aggregate Intrinsic Value	$ 73,751,000
Exercisable at end of year	2,435,322
Options Exercisable, Avg. Life in year	2 years 2 months 12 days
Options Exercisable, Aggregate Intrinsic Value	31,889,000
Range of Exercise Prices per Option $ 0 to $ 0 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, lower limit	$ 37.44
Range of exercise prices, upper limit	$ 39.02
Outstanding at end of year	658,782
Options Outstanding, Avg. Life in Years	3 years 1 month 6 days
Options Outstanding, Aggregate Intrinsic Value	17,677,000
Exercisable at end of year	406,939
Options Exercisable, Avg. Life in year	1 year 4 months 24 days
Options Exercisable, Aggregate Intrinsic Value	11,165,000
Range of Exercise Prices per Option $ 0 to $ 0 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, lower limit	$ 43.88
Range of exercise prices, upper limit	$ 51.63
Outstanding at end of year	2,233,621
Options Outstanding, Avg. Life in Years	4 years 6 months
Options Outstanding, Aggregate Intrinsic Value	34,786,000
Exercisable at end of year	832,631
Options Exercisable, Avg. Life in year	2 years 4 months 24 days
Options Exercisable, Aggregate Intrinsic Value	16,224,000
Range of Exercise Prices per Option $ 0 to $ 0 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, lower limit	$ 54.21
Range of exercise prices, upper limit	$ 63.46
Outstanding at end of year	3,114,182
Options Outstanding, Avg. Life in Years	4 years 7 months 6 days
Options Outstanding, Aggregate Intrinsic Value	21,288,000
Exercisable at end of year	1,195,752
Options Exercisable, Avg. Life in year	2 years 4 months 24 days
Options Exercisable, Aggregate Intrinsic Value	$ 4,500,000