Annual report pursuant to Section 13 and 15(d)

Goodwill - Fair Value Measurement Inputs and Valuation Techniques For Goodwill (Detail)

v3.20.4
Goodwill - Fair Value Measurement Inputs and Valuation Techniques For Goodwill (Detail)
Dec. 31, 2020
Mar. 31, 2020
Dec. 31, 2019
Measurement Input Risk Adjusted Discount Rate [Member] | Digital [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 950   1,000
Measurement Input Risk Adjusted Discount Rate [Member] | Publishing [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 950 1,050 1,000
Measurement Input Risk Adjusted Discount Rate [Member] | Radio Clusters [Member] | Broadcast Networks Enterprise Valuations [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 850   900
Measurement Input, Long-term Revenue Growth Rate [Member] | Digital [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 100    
Measurement Input, Long-term Revenue Growth Rate [Member] | Publishing [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage   50 50
Minimum [Member] | Measurement Input Operating Profit Margin [Member] | Digital [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 340   370
Minimum [Member] | Measurement Input Operating Profit Margin [Member] | Publishing [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 150 0 150
Minimum [Member] | Measurement Input Operating Profit Margin [Member] | Radio Clusters [Member] | Broadcast Networks Enterprise Valuations [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 1,140   3,110
Minimum [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Digital [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage     50
Minimum [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Publishing [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 100    
Minimum [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Radio Clusters [Member] | Broadcast Networks Enterprise Valuations [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 50   70
Maximum [Member] | Measurement Input Operating Profit Margin [Member] | Digital [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 680   2,880
Maximum [Member] | Measurement Input Operating Profit Margin [Member] | Publishing [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 440 390 390
Maximum [Member] | Measurement Input Operating Profit Margin [Member] | Radio Clusters [Member] | Broadcast Networks Enterprise Valuations [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 4,150   3,870
Maximum [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Digital [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage     100
Maximum [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Publishing [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 50    
Maximum [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Radio Clusters [Member] | Broadcast Networks Enterprise Valuations [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Intangible asset measurement input percentage 80   90