Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Apr. 02, 2023	Mar. 31, 2024	Apr. 02, 2023	Oct. 01, 2023
Related Party Transaction [Line Items]
Revenue	$ 1,251,616	$ 1,158,226	$ 2,479,883	$ 2,052,991
Reimbursable costs	13,115	18,952	30,738	40,627
Accounts receivable, net	1,037,883		1,037,883		$ 974,535
Contract assets	102,991		102,991		113,939
Contract liabilities	373,682		373,682		335,044
Related Party
Related Party Transaction [Line Items]
Revenue	14,436	$ 19,888	33,404	$ 42,876
Accounts receivable, net	15,051		15,051		19,944
Contract assets	2,078		2,078		2,723
Contract liabilities	$ 5,051		$ 5,051		$ 3,158