Enterprise-Wide Information (Tables)

12 Months Ended

Dec. 31, 2011

Enterprise-Wide Information [Abstract]

Schedule Of Revenues For Each Group Of Services Provided To External Customers

	2011		2010		2009
Radio audience ratings services	$	340,479	$	317,606	$	307,217
Local market consumer information services		35,173		35,187		34,991
Software applications		35,676		34,138		33,809
All other services		10,982		8,448		8,935
Total revenue	$	422,310	$	395,379	$	384,952

Schedule Of Revenue Attributed To Geographic Areas

	United States		International(1)		Total
2011
Revenues	$	415,869	$	6,441	$	422,310
2010
Revenues	$	390,424	$	4,955	$	395,379
2009
Revenues	$	379,055	$	5,897	$	384,952

(1) The revenues of the individual countries comprising these amounts are not significant.