Reserve for Product Warranty (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2011	Jan. 01, 2011
Product Liability Contingency [Line Items]
Reserve for product warranty, beginning of period	$ 2,245	$ 2,657
Provision for product warranty	174	408
Product warranty costs paid	(805)	(829)
Reserve for product warranty, end of period	$ 1,614	$ 2,236