Annual report pursuant to Section 13 and 15(d)

Key Estimates and Assumptions Used for Enterprise Valuations (Detail)

v2.4.0.6
Key Estimates and Assumptions Used for Enterprise Valuations (Detail)
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Internet and Publishing
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Discount rate   13.50% 8.50%
Long-term revenue market growth rate ranges   3.00% 2.00%
Internet and Publishing | Minimum
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Discount rate 8.50%    
Operating profit margin ranges 0.50% 18.40% 2.00%
Long-term revenue market growth rate ranges 1.50%    
Internet and Publishing | Maximum
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Discount rate 13.50%    
Operating profit margin ranges 22.00% 22.00% 8.40%
Long-term revenue market growth rate ranges 3.00%    
Goodwill-Broadcast
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Discount rate 9.00% 9.00% 9.00%
Goodwill-Broadcast | Minimum
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Long-term revenue market growth rate ranges 0.30% 1.00% 0.25%
Goodwill-Broadcast | Maximum
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Operating profit margin ranges 35.50% 38.00% 36.30%
Long-term revenue market growth rate ranges 15.00% 4.00% 3.50%
Radio Clusters | Goodwill-Broadcast
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Discount rate 9.00%    
Radio Clusters | Goodwill-Broadcast | Minimum
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Operating profit margin ranges 16.90%    
Long-term revenue market growth rate ranges 1.00%    
Radio Clusters | Goodwill-Broadcast | Maximum
      
Discounted Cash Flow Pricing Model, by Assumption [Line Items]      
Operating profit margin ranges 49.20%    
Long-term revenue market growth rate ranges 3.50%