Acquisitions (Narrative) (Details) (USD $)	12 Months Ended							12 Months Ended
	Dec. 31, 2011 AWR Corporation [Member] years	Dec. 31, 2011 AWR Corporation [Member] Amortizable Intangible Assets [Member] years	Dec. 31, 2011 Phase Matrix Inc [Member]	Dec. 31, 2011 Phase Matrix Inc [Member] Amortizable Intangible Assets [Member] years months	Dec. 31, 2010 Privately-Held Company First [Member] years	Dec. 31, 2010 Privately-Held Company Second[Member]	Feb. 01, 2010 Privately-Held Company Second[Member] years	Dec. 31, 2010 Privately-Held Companies [Member] Customer Relationships [Member] years	Dec. 31, 2010 Privately-Held Companies [Member] Acquired Core Technology [Member] years	Dec. 31, 2010 Privately-Held Companies [Member] Non-Compete Agreements [Member] years	Dec. 31, 2010 Privately-Held Companies [Member] Trademarks [Member] years
Business Acquisition [Line Items]
Date of acquisition	June 30, 2011		May 20, 2011		December 31, 2010	February 1, 2010
Acquisition purchase price	$ 66,395,000		$ 40,680,000
Cash paid for acquired company	54,000,000		38,900,000		2,300,000		2,200,000
Term of earn-out arrangement (in number of years)	3
Potential undiscounted payments under the earn-out arrangement, range minimum	0
Potential undiscounted payments under the earn-out arrangement, range maximum	29,000,000
Estimated fair value of the earn-out arrangement	12,000,000
Useful life (in years)		5						5	5	3	3
Intangible asset useful life, minimum (in months)				9
Useful life, maximum (in years)				8
Additional cash paid for acquired company					500,000
Shares of common stock paid for acquired company			1,800,000				3,000,000
Term of payment related to the remaining balance on the purchase of acquired company (in number of years)					3		4
Net tangible assets acquired	10,718,000		5,624,000		187,000		1,100,000
Purchase price allocation, amortizable intangible assets	31,685,000		8,331,000		1,500,000		5,000,000
Purchase price allocation, goodwill	$ 34,003,000		$ 26,725,000		$ 1,100,000		$ 5,000,000