Accounts Receivable - Net and Revenue Recognition (Details) (USD $)	3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 30, 2014	Mar. 30, 2014	Mar. 31, 2013	Sep. 29, 2013
Accounts Receivable - Net and Revenue Recognition
Billed	$ 338,377,000	$ 338,377,000		$ 375,149,000
Unbilled	339,638,000	339,638,000		306,969,000
Contract retentions	23,469,000	23,469,000		23,353,000
Total accounts receivable - gross	701,484,000	701,484,000		705,471,000
Allowance for doubtful accounts	(45,003,000)	(45,003,000)		(44,624,000)
Total accounts receivable - net	656,481,000	656,481,000		660,847,000
Billings in excess of costs on uncompleted contracts	85,970,000	85,970,000		79,507,000
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 and requests for equitable adjustment on contracts	61,000,000	61,000,000		41,000,000
Charges recorded to reverse profit recognized in prior periods	5,300,000
Percentage of project completed	90.00%	90.00%
Remaining estimated cost to complete the related contracts	13,000,000	13,000,000
Additional accounts receivable recorded for project based upon the portion of change orders that the entity believes to have a technical and legal basis for recovery and are probable of collection	10,000,000	10,000,000
Additional revenue recorded for project based upon the portion of change orders that the entity believes to have a technical and legal basis for recovery and are probable of collection	10,000,000
Revenue recognized related to the evaluation of claim amounts		3,400,000	1,100,000
Increase in operating income related to the evaluation of claim amounts		3,400,000	1,100,000
Billed accounts receivable related to U.S. federal government contracts	68,900,000	68,900,000		50,500,000
U.S. federal government unbilled receivables, net of progress payments	69,900,000	69,900,000		79,300,000
Threshold percentage for disclosure of accounts receivable from a single client		10.00%		10.00%
Revenue Recognition and Contract Costs
Net unfavorable operating income adjustments	5,300,000	5,300,000
Liability for anticipated losses	9,200,000	9,200,000		13,300,000
Estimated cost to complete the related contracts	$ 41,100,000	$ 41,100,000
Accounts Receivable
Account receivable major customer
Number of clients exceeding threshold		0		0