Annual report pursuant to Section 13 and 15(d)

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

v3.19.1
Goodwill - Carrying Value and Fair Value of Goodwill (Detail)
 12 Months Ended
Dec. 31, 2018
USD ($)
Accounting
Less Than 10% [Member] | Radio Clusters [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 2
Carrying value including goodwill | $ $ 49,525,000
Less Than 10% [Member] | Digital Media [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 1
Carrying value including goodwill | $ $ 361,000
Greater Than 10% to 20% [Member] | Radio Clusters [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 3
Carrying value including goodwill | $ $ 41,244,000
Greater Than 10% to 20% [Member] | Digital Media [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 2
Carrying value including goodwill | $ $ 9,836,000
Greater Than 20% to 50% [Member] | Radio Clusters [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 6
Carrying value including goodwill | $ $ 100,121,000
Greater Than 50% [Member] | Radio Clusters [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 6
Carrying value including goodwill | $ $ 78,471,000
Greater Than 51% [Member] | Digital Media [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 1
Carrying value including goodwill | $ $ 27,821,000
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 | $ $ 847,000
Greater Than11% to 20% [Member] | Publishing [Member]  
Carrying Amounts And Fair Values Of Financial Instruments [Line Items]  
Number of accounting units | Accounting 1
Carrying value including goodwill | $ $ 3,976,000