Accounts Receivable - Net and Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 01, 2017	Dec. 27, 2015	Oct. 02, 2016
Net accounts receivable and billings in excess of costs on uncompleted contracts
Billed	$ 406,173		$ 364,287
Unbilled	343,186		356,147
Contract retentions	32,683		29,135
Total accounts receivable - gross	782,042		749,569
Allowance for doubtful accounts	(31,258)		(35,233)
Total accounts receivable - net	750,784		714,336
Billings in excess of costs on uncompleted contracts	$ 112,695		88,223
Period for billing and collecting unbilled receivables	12 months
Period for earning majority of billings in excess of costs	12 months
Total accounts receivable related to claims, including requests for equitable adjustment on contracts	$ 44,000		45,000
Gains from claim settlement	0
Billed accounts receivable related to U.S. federal government contracts	76,000		47,400
U.S. federal government unbilled receivables	82,900		92,200
Revenue Recognition and Contract Costs
Net unfavorable operating income adjustments	4,000
Liability for anticipated losses	6,600		$ 6,700
Estimated cost to complete the related contracts	18,100
RME
Revenue Recognition and Contract Costs
Net unfavorable operating income adjustments	2,300
RCM
Net accounts receivable and billings in excess of costs on uncompleted contracts
Cash proceeds from claim settlement		$ 13,400
Claims amount		8,800
Gains from claim settlement		$ 4,600
Revenue Recognition and Contract Costs
Net unfavorable operating income adjustments	$ 1,700