Summary of Restructuring Reserve (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	$ 2,129
Liabilities recognized	219
Payments	(673)
Restructuring reserve, ending balance	1,675
Employee Separation Costs
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	604
Payments	(222)
Restructuring reserve, ending balance	382
Contract Termination Costs
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	1,525
Liabilities recognized	219
Payments	(451)
Restructuring reserve, ending balance	$ 1,293