Annual report pursuant to Section 13 and 15(d)

Common Stock (Narrative) (Details)

v3.20.4
Common Stock (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2020
Oct. 31, 2020
Class of Stock [Line Items]    
Share repurchase program, value   $ 10.0
Percent of total number of outstanding shares of company common stock 5.00%  
Class A Common Stock [Member]    
Class of Stock [Line Items]    
Common Stock, par value $ 0.01  
Voting power percentage 22.00%  
Common stock, shares outstanding 15,624,091  
Percent of total common equity 81.00%  
Class B Common Stock [Member]    
Class of Stock [Line Items]    
Common Stock, par value $ 0.01  
Voting power percentage 78.00%  
Common stock, shares outstanding 3,693,596  
Percent of total common equity 19.00%  
Decrease In Class B Common Stock, Scenario One [Member] | Class A Common Stock [Member]    
Class of Stock [Line Items]    
Voting power percentage 40.00%  
Decrease In Class B Common Stock, Scenario One [Member] | Class B Common Stock [Member]    
Class of Stock [Line Items]    
Voting power percentage 60.00%  
Decrease In Class B Common Stock, Scenario One [Member] | Class B Common Stock [Member] | Maximum [Member]    
Class of Stock [Line Items]    
Common stock, shares outstanding 360,000  
Decrease In Class B Common Stock, Scenario One [Member] | Class B Common Stock [Member] | Minimum [Member]    
Class of Stock [Line Items]    
Common stock, shares outstanding 280,000  
Decrease In Class B Common Stock, Scenario Two [Member] | Class A Common Stock [Member]    
Class of Stock [Line Items]    
Voting power percentage 53.00%  
Decrease In Class B Common Stock, Scenario Two [Member] | Class B Common Stock [Member]    
Class of Stock [Line Items]    
Voting power percentage 47.00%  
Common stock, shares outstanding 280,000  
Decrease In Class B Common Stock, Scenario Three [Member] | Class B Common Stock [Member]    
Class of Stock [Line Items]    
Common stock, shares outstanding 100,000  
Decrease In Class B Common Stock, Scenario Three [Member] | Class B Common Stock [Member] | Minimum [Member]    
Class of Stock [Line Items]    
Common stock, shares outstanding 100,000