Total Stock-Based Compensation Expense, Net (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation charges	$ 3,294	$ 5,615
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation charges	994	808
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation charges		673
Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation charges	1,460	4,012
Performance shares
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation charges	$ 840	$ 122