Stock-Based Compensation Plans - Additional Information 2 (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 24,985	$ 15,449	$ 39,122	$ 27,735
Equity Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			14,700	9,500
Shares granted to employees			355,000	388,700
Restricted stock granted average price			$ 84.96	$ 71.05
Vesting period of shares granted to employees			3 years	3 years
Liability Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			15,200	11,100
Restricted stock granted average price			$ 87.27
Shares granted to employees and directors			207,000	406,100
Vesting period of shares granted to employees			three-year	three-year
Liability Awards | Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock granted average price				$ 75.45
Liability Awards | Non Employee Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock granted average price			$ 88.47	$ 77.26
Shares granted to employees and directors			61,000	18,300
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			$ 4,700	$ 0