Mergers and Acquisitions - Changes in the Carrying Value of Estimated Contingent Earn-Out Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Sep. 27, 2015
Estimated contingent earn-out liabilities
Beginning balance (at fair value)	$ 8,757	$ 4,169	$ 7,030
Estimated earn-out liabilities for acquisitions during the fiscal year	1,604	4,745	4,100
Increases due to re-measurement of fair value reported in interest expense	260	271	136
Net increase (decrease) due to re-measurement of fair value reported as losses (gains) in operating income	(6,923)	2,823	(3,113)
Foreign exchange impact	59	0	(785)
Earn-out payments:
Reported as cash used in operating activities	0	0	0
Reported as cash used in financing activities	(1,319)	(3,251)	(3,199)
Ending balance (at fair value)	$ 2,438	$ 8,757	$ 4,169