Goodwill and Intangible Assets (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Mar. 30, 2014	Mar. 31, 2013	Mar. 30, 2014	Mar. 31, 2013	Sep. 29, 2013
Finite-lived intangible assets
Gross Amount	$ 135,909,000		$ 135,909,000		$ 208,171,000
Accumulated Amortization	(64,926,000)		(64,926,000)		(121,242,000)
Identifiable intangible assets added on acquisition			2,200,000
Foreign currency translation adjustments			2,800,000
Amortization expense for identifiable intangible assets	6,700,000	9,100,000	15,300,000	14,700,000
Estimated amortization expense
2014	11,869,000		11,869,000
2015	19,267,000		19,267,000
2016	15,444,000		15,444,000
2017	13,170,000		13,170,000
2018	6,283,000		6,283,000
Beyond	4,950,000		4,950,000
Total	70,983,000		70,983,000
Non-compete agreements
Finite-lived intangible assets
Weighted-Average Remaining Life			2 years 6 months
Gross Amount	2,123,000		2,123,000		6,160,000
Accumulated Amortization	(1,345,000)		(1,345,000)		(5,247,000)
Client relations
Finite-lived intangible assets
Weighted-Average Remaining Life			4 years 1 month 6 days
Gross Amount	119,364,000		119,364,000		128,839,000
Accumulated Amortization	(51,780,000)		(51,780,000)		(49,189,000)
Backlog
Finite-lived intangible assets
Weighted-Average Remaining Life			6 months
Gross Amount	11,137,000		11,137,000		68,968,000
Accumulated Amortization	(10,159,000)		(10,159,000)		(64,675,000)
Technology and trade names
Finite-lived intangible assets
Weighted-Average Remaining Life			2 years 6 months
Gross Amount	3,285,000		3,285,000		4,204,000
Accumulated Amortization	$ (1,642,000)		$ (1,642,000)		$ (2,131,000)