Accounts Receivable - Net and Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 02, 2017	Jan. 01, 2017	Apr. 02, 2017	Mar. 27, 2016	Oct. 02, 2016
Net accounts receivable and billings in excess of costs on uncompleted contracts
Billed	$ 356,929		$ 356,929		$ 364,287
Unbilled	353,737		353,737		356,147
Contract retentions	35,233		35,233		29,135
Total accounts receivable - gross	745,899		745,899		749,569
Allowance for doubtful accounts	(31,428)		(31,428)		(35,233)
Total accounts receivable - net	714,471		714,471		714,336
Billings in excess of costs on uncompleted contracts	114,341		$ 114,341		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	48,000		$ 48,000		45,000
Revenue Recognition and Contract Costs
Net unfavorable operating income adjustments			8,000
Liabilities for anticipated losses	11,200		11,200		6,700
Estimated cost to complete the related contracts	14,400		14,400
Accounts Receivable | U.S. federal government contracts
Net accounts receivable and billings in excess of costs on uncompleted contracts
Billed accounts receivable related to U.S. federal government contracts	49,900		49,900		47,400
U.S. federal government unbilled receivables	92,400		92,400		$ 92,200
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
Reduction in the revenue related to the evaluation of the claims	4,500
Cash proceeds from claim settlement				$ 13,400
Claims amount				8,800
Gains (loss) from claim settlement	(3,200)	$ 0		$ 4,600
Revenue Recognition and Contract Costs
Net unfavorable operating income adjustments	$ 4,000		$ 5,700