Quarterly report pursuant to Section 13 or 15(d)

Recent Transactions - Acquisitions - Additional Information (Detail)

v3.21.2
Recent Transactions - Acquisitions - Additional Information (Detail) - USD ($)
6 Months Ended
Jun. 01, 2021
Apr. 28, 2021
Jun. 30, 2021
Mar. 08, 2021
Dec. 31, 2020
Dec. 31, 2019
Business Acquisition [Line Items]            
Asset Acquisition, contingent earnout consideration       $ 11,000    
Goodwill     $ 23,785,000   $ 23,757,000 $ 23,998,000
Business combination, recognized identifiable assets acquired and liabilities assumed, contingent liability       $ 100,000    
Triple Threat Trader Newsletter [Member]            
Business Acquisition [Line Items]            
Asset Acquisition, transaction costs     $ 11,000      
KDIA AM AND KDYA AM Sanfrancisco California [Member]            
Business Acquisition [Line Items]            
Payments to Acquire Businesses $ 600,000          
Goodwill $ 4,000          
Centerline New Media Domain And Digital Assets [Member]            
Business Acquisition [Line Items]            
Payments to Acquire Businesses   $ 1,300,000        
Goodwill   $ 24,000