Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Aggregate minimum commitments under non-cancelable operating leases [Abstract]
2012	$ 18,589,000
2013	16,908,000
2014	15,165,000
2015	15,059,000
2016	15,285,000
Thereafter	71,717,000
Total minimum commitments due	152,723,000
Rent expense	19,300,000	21,400,000	17,400,000
Research and development costs reported as allowable expenses	34,300,000	43,200,000	41,300,000
Research and development allowable costs reported as allowable expenses inception to date.	153,500,000
Total revenue of Commercial Resupply Services Contract inception to date	$ 628,000,000
Percentage of Commercial and Resupply Services Contract that is launch and delivery milestones	25.00%