Total Stock-Based Compensation Expense Recognized (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	$ 15,369	$ 17,825	$ 16,458
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	3,984	3,845	1,724
Restricted stock awards and units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	6,880	11,939	11,920
Performance and deferred stock units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	$ 4,505	$ 2,041	$ 2,814