Segment Information (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 321,976,000		$ 372,882,000		$ 989,870,000		$ 1,082,180,000
Operating income (loss)	25,606,000		31,313,000		83,019,000		81,252,000
Identifiable assets	1,244,980,000				1,244,980,000				1,211,454,000	[1]
Capital expenditures	7,696,000		9,061,000		27,529,000		40,801,000
Depreciation and amortization	10,766,000		9,639,000		31,024,000		27,995,000
Intersegment revenues	15,300,000		17,500,000		40,200,000		49,900,000
Launch Vehicles [Member]
Segment Reporting Information [Line Items]
Revenues	127,870,000		140,673,000		396,189,000		393,135,000
Operating income (loss)	11,267,000		9,252,000		33,822,000		26,240,000
Identifiable assets	199,129,000				199,129,000				206,194,000	[1]
Capital expenditures	2,311,000		2,990,000		6,984,000		22,509,000
Depreciation and amortization	4,745,000		4,137,000		13,622,000		11,768,000
Intersegment revenues	14,100,000		15,900,000		36,100,000		44,900,000
Satelites and Space Systems [Member]
Segment Reporting Information [Line Items]
Revenues	88,125,000		129,490,000		282,736,000		370,887,000
Operating income (loss)	8,141,000		12,178,000		29,615,000		30,127,000
Identifiable assets	270,826,000				270,826,000				278,008,000	[1]
Capital expenditures	4,175,000		4,092,000		14,548,000		10,981,000
Depreciation and amortization	2,067,000		2,231,000		6,299,000		6,360,000
Intersegment revenues	1,000,000		1,400,000		3,300,000		4,400,000
Advanced Space Programs [Member]
Segment Reporting Information [Line Items]
Revenues	121,259,000		120,193,000		351,138,000		368,103,000
Operating income (loss)	6,198,000		9,883,000		19,582,000		26,976,000
Identifiable assets	436,913,000				436,913,000				390,059,000	[1]
Capital expenditures	836,000		1,142,000		3,598,000		4,558,000
Depreciation and amortization	2,403,000		1,677,000		6,438,000		5,130,000
Intersegment revenues	200,000		200,000		800,000		600,000
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	(15,278,000)	[2]	(17,474,000)	[2]	(40,193,000)	[2]	(49,945,000)	[2]
Operating income (loss)	0		0		0		(2,091,000)	[3]
Identifiable assets	338,112,000				338,112,000				337,193,000	[1]
Capital expenditures	374,000		837,000		2,399,000		2,753,000
Depreciation and amortization	$ 1,551,000		$ 1,594,000		$ 4,665,000		$ 4,737,000

[1] As of December 31, 2012.

[2] Corporate and other revenues are comprised solely of the elimination of intersegment revenues summarized as follows (in millions): Quarters Ended September 30, Nine Months Ended September 30, 2013 2012 2013 2012 Launch Vehicles $11.1 $15.9 $33.1 $44.9 Satellites and Space Systems 0.8 1.4 3.1 4.4 Advanced Space Programs 0.1 0.2 0.7 0.6 Total intersegment revenues $12.0 $17.5 $36.9 $49.9

[3] 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.