Quarterly report pursuant to Section 13 or 15(d)

Royalty Interests (Details)

v3.19.3
Royalty Interests (Details)
$ in Thousands
9 Months Ended 12 Months Ended
Sep. 30, 2019
USD ($)
a
$ / a
Sep. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
Net Book Value      
Royalty interests acquired $ 29,320   $ 24,303
Total royalty interests 29,320   $ 24,303
Acquisition of royalty interests $ 5,017 $ 0  
1/16th Nonparticipating Perpetual Royalty Interest      
Real Estate Properties [Line Items]      
Nonparticipating perpetual royalty interest rate 6.25%   6.25%
Net Book Value      
1/16th nonparticipating perpetual royalty interest $ 0   $ 0
1/128th Nonparticipating Perpetual Royalty Interest      
Real Estate Properties [Line Items]      
Nonparticipating perpetual royalty interest rate 0.78125%   0.78125%
Net Book Value      
1/128th nonparticipating perpetual royalty interest $ 0   $ 0
Additional real estate acquisitions      
Net Book Value      
Net royalty interests (acre) | a 1,247    
Acquisition of royalty interests $ 4,700    
Average price per net royalty acre acquired (in dollars per acre) | $ / a 3,800