Restructuring - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses related to restructuring initiative	$ 32,473,000	$ 12,314,000	$ 11,095,000
Restructuring liabilities	10,887,000	5,875,000	3,543,000
2009 restructuring initiative
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses related to restructuring initiative			11,100,000
Number of employees			700
Total restructuring costs related to restructuring initiative			23,200,000
Restructuring liabilities			3,543,000
2011 restructuring initiative
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses related to restructuring initiative	32,473,000	12,314,000
Number of employees	491	292
Expected Severance payments period	12 months
Restructuring liabilities	$ 10,887,000	$ 5,875,000