Quarterly report pursuant to Section 13 or 15(d)

Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals)

v3.7.0.1
Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals)
Jun. 30, 2017
a
$ / shares
shares
Dec. 31, 2016
a
$ / shares
shares
Real estate acquired, acres (Acre) 10,065 10,065
Certificates of proprietary interest, par value (in dollars per share) | $ / shares $ 100 $ 100
Certificates of proprietary interest, outstanding (in shares) | shares 0 0
Sub-share certificates of proprietary interest, par value (in dollars per share) | $ / shares $ 0.0333 $ 0.0333
Sub-share certificates of proprietary interest, outstanding (in shares) | shares 7,858,554 7,927,314
Land Surface Rights [Member]    
Land (surface rights), acres (Acre) 877,633 877,488
Royalty Interests in Acres 1_16 [Member]    
Nonparticipating perpetual royalty interest in acres (Acre) 373,777 373,777
Royalty Interests in Acres 1_128 [Member]    
Nonparticipating perpetual royalty interest in acres (Acre) 85,414 85,414