Fair Value - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Jun. 27, 2014	Jun. 28, 2013	Jun. 27, 2014	Jun. 28, 2013	Sep. 27, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Transfers of assets or liabilities between fair value measurement levels	$ 0	$ 0	$ 0	$ 0
Impairment of investment	7,725,000		7,725,000
Fair value of current maturities of long-term debt	50,000,000		50,000,000		56,250,000	[1]
Long-term debt	400,000,000		400,000,000		450,000,000	[1]
Privately Held Equity Investment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment of investment	$ 1,400,000		$ 1,400,000

[1] The condensed consolidated balance sheet as of September 27, 2013 was derived from audited financial statements as of that date, but does not include all disclosures required by accounting principles generally accepted in the United States of America.