Goodwill and Intangibles (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Apr. 01, 2012	Mar. 31, 2013	Apr. 01, 2012	Sep. 30, 2012
Finite-lived intangible assets
Gross Amount	$ 213,248,000		$ 213,248,000		$ 167,528,000
Accumulated Amortization	(106,389,000)		(106,389,000)		(93,297,000)
Amortization expense for intangible assets	9,100,000	6,900,000	14,700,000	15,200,000
Estimated amortization expense
2013	18,622,000		18,622,000
2014	27,025,000		27,025,000
2015	19,591,000		19,591,000
2016	16,353,000		16,353,000
2017	13,853,000		13,853,000
Beyond	11,415,000		11,415,000
Total	106,859,000		106,859,000
Non-compete agreements
Finite-lived intangible assets
Weighted-Average Remaining Life			2 years 10 months 24 days
Gross Amount	6,331,000		6,331,000		5,467,000
Accumulated Amortization	(5,079,000)		(5,079,000)		(4,685,000)
Client relations
Finite-lived intangible assets
Weighted-Average Remaining Life			4 years 10 months 24 days
Gross Amount	131,582,000		131,582,000		99,096,000
Accumulated Amortization	(39,886,000)		(39,886,000)		(31,477,000)
Backlog
Finite-lived intangible assets
Weighted-Average Remaining Life			9 months 18 days
Gross Amount	71,098,000		71,098,000		59,931,000
Accumulated Amortization	(59,802,000)		(59,802,000)		(55,908,000)
Technology and trade names
Finite-lived intangible assets
Weighted-Average Remaining Life			3 years 2 months 12 days
Gross Amount	4,237,000		4,237,000		3,034,000
Accumulated Amortization	$ (1,622,000)		$ (1,622,000)		$ (1,227,000)