Exit Activities - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012 Person	Dec. 31, 2011
Restructuring Cost and Reserve [Line Items]
Restructuings and exit activities, expected reduction in headcount	119
Restructurings and exit activities, expected annualized net savings	$ 4,000,000
Restructurings and exit activities, costs incurred	766,000	1,083,000
Cost of revenues
Restructuring Cost and Reserve [Line Items]
Restructurings and exit activities, costs incurred	500,000	800,000
Operating expense
Restructuring Cost and Reserve [Line Items]
Restructurings and exit activities, costs incurred	$ 300,000	$ 300,000