Accounts Receivable - Net (Details) (USD $)	3 Months Ended	12 Months Ended
	Jan. 01, 2012 M	Oct. 02, 2011
Accounts Receivable - Net
Billed	$ 362,362,000	$ 364,779,000
Unbilled	319,385,000	309,091,000
Contract retentions	19,850,000	15,553,000
Total accounts receivable - gross	701,597,000	689,423,000
Allowance for doubtful accounts	(36,627,000)	(32,244,000)
Total accounts receivable - net	664,970,000	657,179,000
Current billings in excess of costs on uncompleted contracts	93,571,000	84,754,000
Non-current billings in excess of costs on uncompleted contracts	5,811,000	5,832,000
Total billings in excess of costs on uncompleted contracts	99,382,000	90,586,000
Period for billing and collecting unbilled receivables (in months)	12
Period for earning majority of billings in excess of costs (in months)	12
Unbilled accounts receivable related to claims and requests for equitable adjustment on contracts	19,000,000
Billed accounts receivable related to U.S. federal government contracts	94,800,000	88,500,000
U.S. federal government unbilled receivables, net of progress payments	$ 109,900,000	$ 102,700,000
Threshold percentage for disclosure of accounts receivable from a single client	10.00%	10.00%