Total Stock-Based Compensation Expense (Detail) (USD $) In Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010		Sep. 30, 2011	Sep. 30, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense, net for tax	$ 4,131	$ 5,509	[1]	$ 14,655	$ 11,725	[1]
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense, net for tax	1,015	600	[1]	2,885	1,344	[1]
Restricted Stock and Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense, net for tax	2,154	795	[1]	10,305	4,426	[1]
Performance Shares and Deferred Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense, net for tax	$ 962	$ 4,114	[1]	$ 1,465	$ 5,955	[1]

[1] Unrealized tax benefits for the three-month and nine-month periods ended September 30, 2010 was $2.4 million and $5.0 million, respectively.