Receivables (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	$ 542,096,000	$ 499,222,000
Percentage of Commercial Resupply Svcs Contract Launch Delivery	25.00%
Revenue from Commercial Resupply Svcs contract inception to date	1,200,000,000
Contract value of Commercial Resupply Svcs contract	1,900,000,000
Period of performance criteria (in years)	15 years
Potential refund if performance criteria are not met	17,200,000
Billed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	52,396,000	59,496,000
Unbilled [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	489,700,000	439,726,000
Receivables pertaining to the commercial resupply services contract	322,000,000	277,000,000
Incentive fees due incrementally	$ 7,100,000	$ 8,700,000
Period of incentive fees due (in years)	15 years