Stock-Based Compensation (Detail) - Stock-Based Compensation Expense Recognized In Consolidated Statements Of Operations (Parentheticals) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Stock-based compensation expense	$ 9,200	[1]	$ 7,800	[1]	$ 28,021	[1]	$ 24,750	[1]
Retirement Eligible Employees Equity Award [Member]
Stock-based compensation expense	$ 1,500		$ 200		$ 4,700		$ 3,000

[1] The three months ended September 30, 2012 and 2011 included charges of $1.5 million and $0.2 million, respectively, related to awards to retirement-eligible employees, since awards granted to retirement-eligible employees vest on an accelerated basis. The nine months ended September 30, 2012 and 2011 included charges of $4.7 million and $3.0 million, respectively, for retirement-eligible employees.