Quarterly report pursuant to Section 13 or 15(d)

Condensed Consolidated Balance Sheets (Parenthetical)

v3.21.2
Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares
6 Months Ended 12 Months Ended
Jun. 30, 2021
Dec. 31, 2020
Preferred stock and certificates of proprietary interest, par value (in dollars per share) $ 0.01  
Preferred stock and certificates of proprietary interest, shares authorized (in shares) 1,000,000  
Preferred stock and certificates of proprietary interest, shares outstanding (in shares) 0  
Treasury stock (in shares) 1,633 0
Common stock and sub-share certificates of proprietary interest, par value (in dollars per share) $ 0.01  
Common stock and sub-share certificates of proprietary interest, authorized (in shares) 7,756,156  
Common stock and sub-share certificates of proprietary interest, outstanding (in shares) 7,754,523  
Certificates of Proprietary Interest    
Preferred stock and certificates of proprietary interest, par value (in dollars per share)   $ 100
Preferred stock and certificates of proprietary interest, shares outstanding (in shares)   0
Sub-share Certificates in Certificates of Proprietary Interest    
Common stock and sub-share certificates of proprietary interest, par value (in dollars per share)   $ 0.0333
Common stock and sub-share certificates of proprietary interest, outstanding (in shares)   7,756,156
1/16th nonparticipating perpetual royalty interest    
Nonparticipating perpetual royalty interest rate 6.25% 6.25%
1/128th nonparticipating perpetual royalty interest    
Nonparticipating perpetual royalty interest rate 0.78125% 0.78125%