Goodwill And Other Intangible Assets (Narrative) (Details) (USD $)	12 Months Ended			1 Months Ended	0 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jul. 28, 2011	Mar. 23, 2010 Licensing Arrangement With Digimarc Corporation [Member]	Jun. 15, 2010 Purchase Of Technology Portfolio, Trade Name, And Equipment Of Integrated Media Measurement [Member]	Jul. 28, 2011 Zokem Oy [Member]	Dec. 31, 2011 Zokem Oy [Member] years
Acquired Finite-Lived Intangible Assets [Line Items]
Payment for other intangible assets		$ 4,500,000		$ 4,500,000
Amortization of intangible assets, years							5.0
Payment for acquisition of assets	10,553,000	2,500,000			2,500,000
Acquisition of other intangible assets					1,800,000
Acquisition of computer equipment			31,000		300,000
Acquisition of goodwill			7,132,000		400,000
Indefinite- lived intangible assets	0	0
Impairment loss on goodwill	0	0
Contingent consideration with an estimated fair value						900,000
Possible additional cash payments made						12,000,000
Measurement period for weighted range of performance targets, years						4
Acquisition related costs							$ 700,000