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NET INCOME PER COMMON SHARE AND EQUITY PER COMMON SHARE (Details) - $ / shares
 3 Months Ended 12 Months Ended
Mar. 31, 2022
Mar. 31, 2021
Dec. 31, 2021
Shares used in computing basic and diluted net income per share [Abstract]      
Weighted average common shares outstanding during the period for Basic computation (in shares) 9,423,000 9,368,000  
Dilutive effect of employee stock options and awards (in shares) 32,000 39,000  
Weighted average common shares outstanding during the period for Diluted computation (in shares) 9,455,000 9,407,000  
Class A Stock [Member]      
Common Stock [Abstract]      
Common stock, shares authorized (in shares) 15,000,000    
Common stock, shares issued (in shares) 8,556,970 8,502,122  
Common stock, shares outstanding (in shares) 8,556,970 8,502,122  
Common stock, par value (in dollars per share) $ 1.00    
Earnings Per Share [Abstract]      
Equity per common share (in dollars per share) $ 19.16   $ 18.94
Class B Stock [Member]      
Common Stock [Abstract]      
Common stock, shares authorized (in shares) 1,040,000    
Common stock, shares issued (in shares) 881,452 881,452  
Common stock, shares outstanding (in shares) 881,452 881,452  
Common stock, par value (in dollars per share) $ 1.00    
Restricted Stock [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Abstract]      
Shares excluded from calculations of diluted net income per share (in shares)   0