Annual report pursuant to Section 13 and 15(d)

Goodwill - Carrying Value and Fair Value of Goodwill (Detail)

v3.20.4
Goodwill - Carrying Value and Fair Value of Goodwill (Detail)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
USD ($)
Accounting
Less Than 10% [Member] | Radio Clusters [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 1
Carrying value including goodwill | $ $ 8,386
Less Than 10% [Member] | Publishing [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 1
Carrying value including goodwill | $ $ 2,282
Greater Than 21% to 50% [Member] | Digital Media [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 1
Carrying value including goodwill | $ $ 3,164
Greater Than 51% [Member] | Radio Clusters [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 3
Carrying value including goodwill | $ $ 43,617
Greater Than 51% [Member] | Publishing [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 1
Carrying value including goodwill | $ $ 391