Segment Information (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Segment Reporting Information [Line Items]
Revenues	$ 335,451,000	$ 342,170,000	$ 350,599,000	$ 317,703,000	$ 346,142,000	$ 314,519,000	$ 337,726,000	$ 296,190,000	$ 1,345,923,000		$ 1,294,577,000		$ 1,125,295,000
Operating income	22,203,000	24,668,000	22,807,000	10,116,000	24,065,000	19,356,000	12,228,000	17,365,000	79,794,000		73,014,000		52,293,000
Identifiable assets	1,130,800,000				1,062,536,000				1,130,800,000		1,062,536,000		929,481,000
Capital expenditures									59,815,000		83,702,000		45,343,000
Depreciation and amortization									32,739,000		26,186,000		19,208,000
Intersegment revenues									125,100,000		60,600,000		11,900,000
Launch Vehicles [Member]
Segment Reporting Information [Line Items]
Revenues									483,177,000		434,511,000		440,172,000
Operating income									14,147,000		21,188,000		14,166,000
Identifiable assets	210,642,000				212,360,000				210,642,000		212,360,000		151,249,000
Capital expenditures									27,999,000		50,001,000		10,115,000
Depreciation and amortization									14,293,000		9,412,000		5,954,000
Intersegment revenues									118,300,000		53,400,000		8,000,000
Satelites and Space Systems [Member]
Segment Reporting Information [Line Items]
Revenues									553,797,000		497,015,000		352,252,000
Operating income									37,623,000		33,775,000		27,329,000
Identifiable assets	282,344,000				268,804,000				282,344,000		268,804,000		178,233,000
Capital expenditures									12,433,000		10,675,000		9,931,000
Depreciation and amortization									6,841,000		5,917,000	[1]	4,780,000	[1]
Intersegment revenues									5,600,000		5,900,000		3,700,000
Advanced Space Programs [Member]
Segment Reporting Information [Line Items]
Revenues									434,036,000		423,614,000		344,787,000
Operating income									28,024,000		20,999,000		10,798,000
Identifiable assets	254,769,000				188,184,000				254,769,000		188,184,000		91,981,000
Capital expenditures									13,515,000		19,586,000		21,739,000
Depreciation and amortization									5,033,000		4,522,000	[1]	3,983,000	[1]
Intersegment revenues									1,200,000		1,300,000		200,000
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues									(125,087,000)	[2]	(60,563,000)	[2]	(11,916,000)	[2]
Operating income									0		(2,948,000)	[3]	0
Identifiable assets	383,045,000				393,188,000				383,045,000		393,188,000		508,018,000
Capital expenditures									5,868,000		3,440,000		3,558,000
Depreciation and amortization									$ 6,572,000		$ 6,335,000		$ 4,491,000

[1] Prior period amounts have been reclassified to conform to the current period presentation.

[2] Corporate and other revenues are comprised solely of the elimination of intersegment revenues. Intersegment revenues are summarized as follows (in millions): Launch Vehicles Years Ended December 31, 2011 2010 2009 118.3 53.4 8.0 Satellites and Space Systems Years Ended December 31, 2011 2010 2009 5.6 5.9 3.7 Advanced Space Programs Years Ended December 31, 2011 2010 2009 1.2 1.3 0.2 Total intersegment revenues Years Ended December 31, 2011 2010 2009 125.1 60.6 11.9

[3] The corporate and other operating loss in 2010 is comprised of unallocated corporate-level costs and includes $1.6 million of transaction expenses incurred in connection with a business acquisition (see Note 2).