Allowance for Doubtful Accounts - Schedule of Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balances at Beginning of Period	$ 19,296	$ 25,212	$ 21,158
Charged/ (Credited) to Costs and Expenses	6,041	741	8,988
Asset Write-Offs, Less Recoveries	(4,268)	(6,657)	(4,934)
Balances at End of Period	$ 21,069	$ 19,296	$ 25,212