Annual report pursuant to Section 13 and 15(d)

Broadcast Licenses - Carrying Value and Fair Value of Broadcast Licenses (Detail)

v3.20.1
Broadcast Licenses - Carrying Value and Fair Value of Broadcast Licenses (Detail) - Broadcast Licenses [Member]
$ in Thousands
 3 Months Ended 12 Months Ended
Sep. 30, 2019
USD ($)
Accounting
Dec. 31, 2019
USD ($)
Accounting
Less than or equal to 25% [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Number Of Business Reporting Units For Market Based Services | Accounting 7 10
Excess Of Estimated Undiscounted Cash Flows Over Carrying Value | $ $ 101,948 $ 138,730
>26%-50% [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Number Of Business Reporting Units For Market Based Services | Accounting   5
Excess Of Estimated Undiscounted Cash Flows Over Carrying Value | $   $ 76,364
>26%-50% [Member] | Station Operating Income [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Number Of Business Reporting Units For Market Based Services | Accounting   1
Excess Of Estimated Undiscounted Cash Flows Over Carrying Value | $   $ 9,333
>51% to 75% [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Number Of Business Reporting Units For Market Based Services | Accounting   2
Excess Of Estimated Undiscounted Cash Flows Over Carrying Value | $   $ 8,150
>51% to 75% [Member] | Station Operating Income [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Number Of Business Reporting Units For Market Based Services | Accounting   4
Excess Of Estimated Undiscounted Cash Flows Over Carrying Value | $   $ 37,945
> than 76% [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Number Of Business Reporting Units For Market Based Services | Accounting   8
Excess Of Estimated Undiscounted Cash Flows Over Carrying Value | $   $ 63,869
> than 76% [Member] | Station Operating Income [Member]    
Indefinite-lived Intangible Assets [Line Items]    
Number Of Business Reporting Units For Market Based Services | Accounting   1
Excess Of Estimated Undiscounted Cash Flows Over Carrying Value | $   $ 4,281