Stock-Based Compensation Plans - Additional Information 1 (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014 Plans	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Acceleration of stock-based compensation expense	$ 10,000,000
Stock-based compensation expense	70,681,000	64,369,000	52,770,000
Active equity-based stock plans	2
Stock Appreciation Rights (SARs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock option outstanding	1,966,549	2,582,074	3,433,362	4,558,609
Former Executive Chairman
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	6,700,000
Termination costs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 2,999,000