Restructuring (Summary of Restructuring Charges) (Detail) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Restructuring Reserve [Roll Forward]
Restructuring Reserve, June 30,2012	$ 11,700,000
Expense	(160,000)	(14,700,000)	0	(14,907,000)	0
Utilization	(2,600,000)
Restructuring Reserve, September 30,2012	9,300,000	11,700,000		9,300,000
Severance [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve, June 30,2012	11,600,000
Expense	0
Utilization	(2,500,000)
Restructuring Reserve, September 30,2012	9,100,000			9,100,000
Other [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve, June 30,2012	100,000
Expense	(160,000)
Utilization	(100,000)
Restructuring Reserve, September 30,2012	$ 200,000			$ 200,000