Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Jun. 29, 2012	Jul. 01, 2011	Jun. 29, 2012	Jul. 01, 2011
Finite-Lived Intangible Assets
Amortization expense for intangible assets	$ 1,100,000	$ 700,000	$ 2,848,000	$ 2,280,000
Future amortization expense, remaining fiscal year 2012	1,100,000		1,100,000
Future amortization expense, fiscal year 2013	4,300,000		4,300,000
Future amortization expense, fiscal year 2014	3,400,000		3,400,000
Future amortization expense, fiscal year 2015	3,000,000		3,000,000
Future amortization expense, fiscal year 2016 and thereafter	$ 11,100,000		$ 11,100,000