Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 28, 2012	Sep. 30, 2011	Oct. 01, 2010
Finite-Lived Intangible Assets [Line Items]
Amortization expense for intangible assets	$ 4,879,000	$ 2,948,000	$ 3,320,000
Future amortization expense, fiscal year 2013	4,300,000
Future amortization expense, fiscal year 2014	6,200,000
Future amortization expense, fiscal year 2015	4,800,000
Future amortization expense, fiscal year 2016	2,400,000
Future amortization expense, fiscal year 2017 and thereafter	$ 9,100,000