Stock Incentive Plans and Stock Purchase Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants and awards under Stock Incentive Plans	7,300,000
Stock-based compensation expense related to its Stock Incentive Plans and Stock Purchase Plan	$ 31,300,000	$ 28,400,000	$ 27,100,000
Aggregate fair value of restricted shares, vested	33,300,000	23,000,000	19,000,000
Weighted average grant-date fair value of restricted and deferred stock awards granted	$ 46.48	$ 30.06	$ 35.50
Stock-based compensation cost related to non-vested stock options remaining to be recognized as compensation expense, weighted-average period in years	1 year 4 months 24 days
Unrecognized Compensation Expense related to Nonvested Shares	26,300,000
Aggregate intrinsic value of stock options exercised	35,400,000	18,100,000	14,100,000
Unrecognized Compensation Expense related to Stock Options	33,000
Excess tax benefit related to employee stock incentive plans	18,981,000	6,198,000	7,111,000
Cash proceeds received from the exercise of stock options	$ 18,900,000	$ 20,800,000	$ 24,500,000
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of options, maximum years	10 years
Number of years over which options become exercisable on a pro rata basis	3 years
Stock-based compensation cost related to non-vested stock options remaining to be recognized as compensation expense, weighted-average period in years	3 months 18 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of years over which options become exercisable on a pro rata basis	3 years
Deferred Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of years over which options become exercisable on a pro rata basis	5 years
1996 Non-Qualified Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of market value of common stock at which employees are permitted to purchase	85.00%
Percentage of discount received by participating employees	15.00%
Shares reserved for issuance	595,000
Shares issued under Non-Qualified Plan	250,000