Goodwill and Intangible Assets - Gross Amount and Accumulated Amortization of Acquired Finite-lived Intangibles (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 03, 2022	Oct. 03, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 92,026	$ 118,971
Accumulated Amortization	(58,083)	(80,981)
Net Amount	$ 33,943	37,990
Client relations
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	5 years 8 months 12 days
Gross Amount	$ 44,287	69,455
Accumulated Amortization	(20,847)	(43,984)
Net Amount	$ 23,440	25,471
Backlog
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	9 months 18 days
Gross Amount	$ 34,088	34,577
Accumulated Amortization	(29,811)	(30,670)
Net Amount	$ 4,277	3,907
Trade names
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	3 years 10 months 24 days
Gross Amount	$ 13,651	14,939
Accumulated Amortization	(7,425)	(6,327)
Net Amount	$ 6,226	$ 8,612