Goodwill and Intangibles (Details 2) (USD $)	12 Months Ended
	Oct. 02, 2011	Oct. 03, 2010	Sep. 27, 2009
Finite-lived intangible assets
Gross Amount	$ 142,416,000	$ 80,872,000
Accumulated Amortization	(61,363,000)	(34,877,000)
Amortization expense for intangible assets	28,000,000	12,700,000	9,800,000
Estimated amortization expense
2012	26,203,000
2013	12,146,000
2014	10,875,000
2015	10,588,000
2016	9,096,000
Beyond	12,145,000
Total	81,053,000
Non-compete agreements
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	2.0
Gross Amount	5,175,000	4,295,000
Accumulated Amortization	(3,430,000)	(2,177,000)
Client relations
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	6.3
Gross Amount	81,619,000	41,020,000
Accumulated Amortization	(17,951,000)	(8,351,000)
Backlog
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	0.9
Gross Amount	52,938,000	35,311,000
Accumulated Amortization	(39,452,000)	(24,329,000)
Technology and trade names
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	4.5
Gross Amount	2,684,000	246,000
Accumulated Amortization	$ (530,000)	$ (20,000)