Goodwill and Intangible Assets - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 02, 2016	Sep. 27, 2015	Sep. 28, 2014
Finite-lived intangible assets
Gross Amount	$ 144,044	$ 112,116
Accumulated Amortization	(95,082)	(71,784)
Foreign currency translation adjustments	1,100
Amortization expense for intangible assets	22,100	20,200	$ 27,300
Estimated amortization expense
2017	22,617
2018	14,295
2019	6,989
2020	3,755
2021	666
Beyond	640
Total	$ 48,962
Non-compete agreements
Finite-lived intangible assets
Weighted-Average Remaining Life	7 months 6 days
Gross Amount	$ 881	819
Accumulated Amortization	$ (840)	(587)
Client relations
Finite-lived intangible assets
Weighted-Average Remaining Life	3 years
Gross Amount	$ 112,367	106,676
Accumulated Amortization	$ (83,514)	(67,726)
Backlog
Finite-lived intangible assets
Weighted-Average Remaining Life	2 years 2 months 12 days
Gross Amount	$ 23,018	2,115
Accumulated Amortization	$ (7,536)	(1,444)
Technology and trade names
Finite-lived intangible assets
Weighted-Average Remaining Life	4 years
Gross Amount	$ 7,778	2,506
Accumulated Amortization	$ (3,192)	$ (2,027)