Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Detail)

v3.19.3
Subsequent Events - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Oct. 31, 2019
Oct. 05, 2019
Sep. 27, 2019
Sep. 26, 2019
Aug. 13, 2019
Jul. 05, 2019
Dec. 31, 2019
Sep. 30, 2019
Sep. 30, 2019
Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Agreement to sell business                 $ 4,202,000 $ 8,518,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period                 430,384  
Restricted Stock [Member] | Executive Officer [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period           41,323        
Vesting period           2 years        
Subsequent Event [Member] | Restricted Stock [Member] | Executive Officer [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   66,667                
Vesting period   2 years                
Radio Stations [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Agreement to sell business     $ 0 $ 8,200,000 $ 8,700,000          
Pretax loss on sale of assets     $ (1,300,000) $ (4,700,000)       $ 9,900,000    
Radio Stations [Member] | Subsequent Event [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Agreement to sell business $ 200,000                  
Radio Stations [Member] | Scenario, Forecast [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Pretax loss on sale of assets             $ 1,700,000