Restructuring - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses related to restructuring initiative		$ 4,938
Restructuring liabilities	4,205		10,887
2011 restructuring initiative
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses related to restructuring initiative		$ 4,900
Number of employees	337
Expected Severance payments period	9 months