Stock-Based Compensation (Detail) - Stock-Based Compensation Expense By Award Type (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Stock appreciation rights	$ 36,378,000		$ 32,865,000		$ 32,634,000
Stock-based compensation expense	36,400,000	[1]	32,900,000	[1]	32,600,000	[1]
Stock Appreciation Rights (SARs) [Member]
Stock appreciation rights	6,400,000		4,400,000		4,600,000
Common Stock Equivalents (CSEs) [Member]
Stock-based compensation expense	500,000		500,000		500,000
Restricted Stock Units (RSUs) [Member]
Stock-based compensation expense	$ 29,500,000		$ 28,000,000		$ 27,500,000

[1] Includes charges of $5.1 million in 2012 and $3.1 million in both 2011 and 2010 for awards to retirement-eligible employees since these awards vest on an accelerated basis