Acquisitions (Narrative) (Details) (USD $)	2 Months Ended	12 Months Ended		12 Months Ended		11 Months Ended	12 Months Ended		12 Months Ended					12 Months Ended					12 Months Ended					12 Months Ended
	Dec. 31, 2011 Worldwide Information Network Systems, Inc. [Member]	Dec. 31, 2011 Worldwide Information Network Systems, Inc. [Member] Y	Nov. 15, 2011 Worldwide Information Network Systems, Inc. [Member]	Dec. 31, 2011 Worldwide Information Network Systems, Inc. [Member] Backlog [Member] Y	Dec. 31, 2011 Worldwide Information Network Systems, Inc. [Member] Customer Relationships [Member] Y	Dec. 31, 2011 TranTech, Inc. [Member]	Dec. 31, 2011 TranTech, Inc. [Member] Y	Feb. 10, 2011 TranTech, Inc. [Member]	Dec. 31, 2011 TranTech, Inc. [Member] Backlog [Member] Y	Dec. 31, 2011 TranTech, Inc. [Member] Customer Relationships [Member] Y	Dec. 31, 2011 MTCSC, Inc. [Member] Y	Dec. 31, 2010 MTCSC, Inc. [Member]	Dec. 23, 2010 MTCSC, Inc. [Member]	Dec. 31, 2011 MTCSC, Inc. [Member] Backlog [Member] Y	Dec. 31, 2011 MTCSC, Inc. [Member] Customer Relationships [Member] Y	Dec. 31, 2011 Security and Intelligence Solutions Business [Member] Y	Dec. 31, 2010 Security and Intelligence Solutions Business [Member]	Oct. 08, 2010 Security and Intelligence Solutions Business [Member]	Dec. 31, 2011 Security and Intelligence Solutions Business [Member] Backlog [Member] Y	Dec. 31, 2011 Security and Intelligence Solutions Business [Member] Customer Relationships [Member] Y	Dec. 31, 2011 Sensor Technologies Inc. [Member] Y	Dec. 31, 2010 Sensor Technologies Inc. [Member]	Jan. 15, 2010 Sensor Technologies Inc. [Member]	Dec. 31, 2011 Sensor Technologies Inc. [Member] Backlog [Member] Y	Dec. 31, 2011 Sensor Technologies Inc. [Member] Customer Relationships [Member] Y	Dec. 31, 2011 Sensor Technologies Inc. [Member] Non-Compete Agreements [Member] Y	Dec. 31, 2011 DDK Technologies Group [Member] Y	Dec. 31, 2011 DDK Technologies Group [Member] Backlog [Member] Y	Dec. 31, 2011 DDK Technologies Group [Member] Customer Relationships [Member] Y
Number of employees within acquired entity			199					57					366					370					252
Percentage of employees within acquired entity with security clearances			96.00%										90.00%					93.00%					100.00%
Business acquisition, purchase price	$ 90,000,000	$ 90,000,000				$ 21,500,000	$ 21,500,000				$ 76,700,000					$ 60,000,000					$ 241,400,000						$ 14,000,000
Working capital adjustment																					600,000
Amount deposited in escrow account			9,000,000										11,300,000					1,000,000
Escrow Claim Expiry Period			18 months										18 months					6 months
Balance in escrow account	9,000,000	9,000,000									11,300,000					400,000
Revenue of acquiree since acquisition date	8,500,000					12,500,000
Net income of acquiree since acquisition date	700,000					900,000
Business acquisition transaction costs expensed		600,000					300,000				100,000	700,000				100,000	700,000				0	200,000
Business acquisition, total assets	100,400,000	100,400,000				23,800,000	23,800,000				94,800,000					62,000,000											14,500,000
Business acquisition, total liabilities	10,400,000	10,400,000				2,300,000	2,300,000				18,000,000					2,000,000											500,000
Acquired intangible assets	18,700,000	18,700,000				5,000,000	5,000,000				8,700,000					13,000,000											4,200,000
Goodwill deductible for tax purposes	62,200,000	62,200,000				14,600,000	14,600,000									40,300,000											8,900,000
Period of expected tax deductible goodwill amount from business acquisition (years)		15 years					15 years									15 years					15 years						15 years
Goodwill not deductible for tax purposes											60,100,000
Other intangible assets related to acquisition				700,000	18,000,000				400,000	4,600,000				600,000	8,100,000				1,500,000	11,500,000				7,800,000	85,200,000	300,000		300,000	3,900,000
Period of Eligibility for Noncompete Agreements																					4 years
Estimated useful lives of intangible assets (in years)				1	20				1	20				1	20				1	20				1	20	4		1	20
Weighted-average amortization period for intangible assets (years)		19.3					18.5				18.7					17.9					18.4						18.8
Estimated tax liabilities of indemnification assets																							800,000
Indemnification asset																							800,000
Amount of indemnification assets collected																					$ 800,000