Quarterly report pursuant to Section 13 or 15(d)

Acquisitions and Recent Transactions - Additional Information (Detail)

v3.10.0.1
Acquisitions and Recent Transactions - Additional Information (Detail) - USD ($)
1 Months Ended 6 Months Ended 9 Months Ended
Sep. 28, 2018
Sep. 11, 2018
Sep. 05, 2018
Aug. 28, 2018
Aug. 09, 2018
Aug. 07, 2018
Jul. 25, 2018
Jun. 29, 2018
Jun. 25, 2018
May 31, 2018
May 04, 2018
Apr. 19, 2018
Apr. 10, 2018
Apr. 09, 2018
Mar. 28, 2018
Feb. 28, 2018
Aug. 06, 2018
Jul. 24, 2018
Jun. 20, 2018
May 24, 2018
Apr. 30, 2018
Jun. 30, 2018
Sep. 30, 2018
Sep. 30, 2017
Jul. 23, 2018
Dec. 31, 2017
May 19, 2017
Dec. 31, 2016
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Debt instrument, interest rate, stated percentage                                             4.58%          
Common stock, equity distributions, per share, declared     $ 0.0650             $ 0.0650           $ 0.0650                        
Payments of equity distributions, common stock $ 1,700,000             $ 1,700,000             $ 1,700,000               $ 5,104,000 $ 5,089,000        
Business Combination, Consideration Transferred                                             11,180,000          
Goodwill                                             26,789,000     $ 26,424,000   $ 25,613,000
Business combination, consideration transferred                                             4,320,000 1,690,000        
Business combination acquisition related costs                                             200,000 100,000        
Proceeds from sale of assets                                             8,518,000 $ 602,000        
Proceeds from sale of property, plant, and equipment                                       $ 800,000                
Agreement to sell assets in cash                                       1,000,000                
Gain (loss) on disposition of assets                                       $ 200,000                
Time Brokerage Agreement [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Business combination, consideration transferred                                         $ 1,200,000              
Fee for not exercising purchase option                                         $ 100,000              
HearItFirst.com (Asset Purchase) [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Business Combination, Consideration Transferred                       $ 70,000                     $ 70,000          
KTRB-AM [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Payment for asset acquisition   $ 5,100,000                                                    
Transaction costs related to asset acquisition   $ 200,000                                                    
Hilary Kramer Financial Newsletter [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Business Combination, Consideration Transferred         $ 2,000,000                                              
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, deferred subscription liabilities         1,500,000                                              
Payments to acquire businesses, gross         400,000                                              
Additional contingent earnout consideration paid         100,000                                              
Business combination, liabilities arising from contingencies, amount recognized         40,617                                              
Business combination liabilities arising from contingencies amount recognized discounted present value         39,360                                              
Goodwill         $ 300,000                                              
Just1Word [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Business combination, liabilities arising from contingencies, amount recognized           $ 12,750                                            
Business combination liabilities arising from contingencies amount recognized discounted present value           12,212                                            
Business acquisition cost of acquired entity cash paid net           300,000                                            
Business combination, contingent consideration arrangements payment           $ 100,000                                            
KZTS-AM [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Payment for asset acquisition             $ 200,000                                          
Transaction costs related to asset acquisition             $ 30,000                                          
Childrens Ministry Dealscom Website [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Payments to acquire businesses, gross                                   $ 3,500,000                    
Goodwill                                   700,000                    
Business combination, consideration transferred                                   3,700,000                    
Payment up on fulfillments of certain post-closing requirements                                   $ 200,000                    
Business combination cash consideration description                                   $0.2 million in cash within twelve months from the closing date provided that the seller meet certain post-closing requirements with regard to intellectual property.                    
KGBIFM [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Proceeds from sale of assets                                 $ 3,200,000                      
Gain (loss) on disposition of assets                                 $ (2,400,000)         $ (3,200,000)            
KDXE-FM [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Business Combination, Consideration Transferred                 $ 1,100,000                                      
Goodwill                 $ 7,400                                      
WQVN-AM [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Proceeds from sale of assets       $ 3,500,000                                                
Gain (loss) on disposition of assets       $ (4,700,000)                                                
WBIX-AM [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Proceeds from sale of assets                                     $ 700,000                  
Gain (loss) on disposition of assets                                     $ 200,000                  
KCRO-AM and KOTK-AM [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Gain (loss) on disposition of assets                                           $ (1,600,000)            
Agreement to sell assets in cash                                                 $ 1,400,000      
Senior Secured Debt [Member]                                                        
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]                                                        
Debt repurchased                     $ 4,000,000   $ 4,000,000 $ 2,000,000                            
Debt instrument, interest rate, stated percentage                     6.75%   6.75% 6.75%                 6.75%       6.75%  
Repayments of long-term debt                     $ 3,800,000   $ 3,900,000 $ 1,900,000                            
Debt instrument, redemption price, percentage of principal amount redeemed                     94.25%   96.25% 96.50%                            
Gain (Loss) on repurchase of debt instrument                     $ 100,000   $ 63,000 $ 27,000