Goodwill and Intangibles (Details 2) (USD $)	12 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Oct. 03, 2010
Finite-lived intangible assets
Gross Amount	$ 167,528,000	$ 142,416,000
Accumulated Amortization	(93,297,000)	(61,363,000)
Amortization expense for intangible assets	29,600,000	28,000,000	12,700,000
Estimated amortization expense
2013	17,834,000
2014	14,272,000
2015	13,229,000
2016	11,617,000
2017	9,563,000
Beyond	7,716,000
Total	74,231,000
Non-compete agreements
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	1.3
Gross Amount	5,467,000	5,175,000
Accumulated Amortization	(4,685,000)	(3,430,000)
Client relations
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	5.6
Gross Amount	99,096,000	81,619,000
Accumulated Amortization	(31,477,000)	(17,951,000)
Backlog
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	1.1
Gross Amount	59,931,000	52,938,000
Accumulated Amortization	(55,908,000)	(39,452,000)
Technology and trade names
Finite-lived intangible assets
Weighted-Average Remaining Life (in years)	3.8
Gross Amount	3,034,000	2,684,000
Accumulated Amortization	$ (1,227,000)	$ (530,000)