Accounts Receivable - Net (Details) (USD $)	12 Months Ended
	Sep. 30, 2012 M	Oct. 02, 2011
Accounts Receivable - Net
Billed	$ 362,331,000	$ 364,779,000
Unbilled	355,793,000	309,091,000
Contract retentions	17,908,000	15,553,000
Total accounts receivable - gross	736,032,000	689,423,000
Allowance for doubtful accounts	(35,552,000)	(32,244,000)
Total accounts receivable - net	700,480,000	657,179,000
Current billings in excess of costs on uncompleted contracts	90,909,000	84,754,000
Non-current billings in excess of costs on uncompleted contracts	4,410,000	5,832,000
Total billings in excess of costs on uncompleted contracts	95,319,000	90,586,000
Period for billing and collecting unbilled receivables (in months)	12
Unbilled accounts receivable related to claims and requests for equitable adjustment on contracts	21,000,000	16,000,000
Period for earning majority of billings in excess of costs (in months)	12
Billed accounts receivable related to U.S. federal government contracts	65,900,000	88,500,000
U.S. federal government unbilled receivables, net of progress payments	$ 100,400,000	$ 102,700,000
Threshold percentage for disclosure of accounts receivable from a single client	10.00%	10.00%