Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 Segment		Dec. 31, 2012		Dec. 31, 2011
Segment Information [Abstract]
Number of reportable business segments									3
Segment Reporting Information [Line Items]
Revenues	$ 375,401	$ 321,976	$ 333,081	$ 334,813	$ 354,589	$ 372,882	$ 371,268	$ 338,030	$ 1,365,271		$ 1,436,769		$ 1,345,923
Operating income	30,526	25,606	26,306	31,107	31,320	31,313	26,092	23,846	113,545		112,571		79,794
Identifiable assets	1,284,761				1,211,454				1,284,761		1,211,454		1,130,800
Capital expenditures									35,655		52,175		59,815
Depreciation and amortization									41,479		37,339		32,739
Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues									43,300		56,800		125,100
Launch Vehicles [Member]
Segment Reporting Information [Line Items]
Revenues									551,709		527,287		483,177
Operating income									48,831		36,131		14,147
Identifiable assets	195,294				206,194				195,294		206,194		210,642
Capital expenditures									8,882		26,066		27,999
Depreciation and amortization									17,990		15,891		14,293
Launch Vehicles [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues									38,200		50,200		118,300
Satelites and Space Systems [Member]
Segment Reporting Information [Line Items]
Revenues									387,505		496,152		553,797
Operating income									33,938		46,222		37,623
Identifiable assets	288,343				278,008				288,343		278,008		282,344
Capital expenditures									18,359		16,345		12,433
Depreciation and amortization									8,366		8,563		6,841
Satelites and Space Systems [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues									4,100		5,700		5,600
Advanced Space Programs [Member]
Segment Reporting Information [Line Items]
Revenues									469,400		470,102		434,036
Operating income									30,776		32,309		28,024
Identifiable assets	448,015				390,059				448,015		390,059		254,769
Capital expenditures									4,652		5,781		13,515
Depreciation and amortization									8,872		6,575		5,033
Advanced Space Programs [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues									1,000		900		1,200
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues									(43,343)	[1]	(56,772)	[1]	(125,087)	[1]
Operating income									0		(2,091)	[2]	0
Identifiable assets	353,109				337,193				353,109		337,193		383,045
Capital expenditures									3,762		3,983		5,868
Depreciation and amortization									$ 6,251		$ 6,310		$ 6,572

[1] Corporate and other revenues are comprised solely of the elimination of intersegment revenues. Intersegment revenues are summarized as follows (in millions): Years Ended December 31, 2013 2012 2011 Launch Vehicles $38.2 $50.2 $118.3 Satellites and Space Systems $4.1 $5.7 $5.6 Advanced Space Programs $1.0 $0.9 $1.2 Total intersegment revenues $43.3 $56.8 $125.1

[2] The corporate and other operating loss in 2012 is comprised solely of professional fees and other costs related to a potential acquisition that was not consummated.