Goodwill and Intangible Assets - Gross Amount and Accumulated Amortization of Acquired Finite-lived Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2022	Oct. 03, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 90,695	$ 118,971
Accumulated Amortization	(54,160)	(80,981)
Net Amount	$ 36,535	37,990
Client relations
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	6 years 4 months 24 days
Gross Amount	$ 43,646	69,455
Accumulated Amortization	(18,723)	(43,984)
Net Amount	$ 24,923	25,471
Backlog
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	1 year 2 months 12 days
Gross Amount	$ 32,113	34,577
Accumulated Amortization	(28,573)	(30,670)
Net Amount	$ 3,540	3,907
Technology and trade names
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Life (in Years)	4 years 3 months 18 days
Gross Amount	$ 14,936	14,939
Accumulated Amortization	(6,864)	(6,327)
Net Amount	$ 8,072	$ 8,612