Accounts Receivable - Net (Details) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 item	Sep. 30, 2012 item
Accounts Receivable - Net
Billed	$ 353,299,000	$ 353,299,000	$ 362,331,000
Unbilled	295,411,000	295,411,000	355,793,000
Contract retentions	27,892,000	27,892,000	17,908,000
Total accounts receivable - gross	676,602,000	676,602,000	736,032,000
Allowance for doubtful accounts	(44,382,000)	(44,382,000)	(35,552,000)
Total accounts receivable - net	632,220,000	632,220,000	700,480,000
Current billings in excess of costs on uncompleted contracts	85,352,000	85,352,000	90,909,000
Non-current billings in excess of costs on uncompleted contracts			4,410,000
Total billings in excess of costs on uncompleted contracts	85,352,000	85,352,000	95,319,000
Period for billing and collecting unbilled receivables		12 months
Period for earning majority of billings in excess of costs		12 months
Unbilled accounts receivable related to claims and requests for equitable adjustment on contracts	37,000,000	37,000,000	21,000,000
Loss on uncollectible accounts receivable related to claims	17,000,000	17,000,000	0
Billed accounts receivable related to U.S. federal government contracts	71,800,000	71,800,000	65,900,000
U.S. federal government unbilled receivables, net of progress payments	$ 67,200,000	$ 67,200,000	$ 100,400,000
Number of clients exceeding threshold		0	0
Threshold percentage for disclosure of accounts receivable from a single client		10.00%	10.00%