Activity Related to Accrued Warranties (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Product Warranty Liability [Line Items]
Beginning Balance	$ 2,359	$ 2,365	$ 1,857
Provision for warranty expense	3,541	3,071	2,953
Warranty expired	(3,536)	(3,077)	(2,445)
Ending Balance	$ 2,364	$ 2,359	$ 2,365