Quarterly report pursuant to Section 13 or 15(d)

Real Estate Activity - Land Sales (Details)

v3.10.0.1
Real Estate Activity - Land Sales (Details)
$ in Thousands
1 Months Ended 9 Months Ended
Sep. 30, 2018
USD ($)
a
Aug. 31, 2018
USD ($)
a
Mar. 31, 2018
USD ($)
a
Feb. 28, 2018
USD ($)
a
May 31, 2017
USD ($)
a
Sep. 30, 2018
USD ($)
a
Sep. 30, 2017
USD ($)
a
Real Estate [Line Items]              
Approximate number of acres sold (acres) | a           166.8 11.02
Contract sale price | $           $ 4,293 $ 220
Loving County              
Real Estate [Line Items]              
Approximate number of acres sold (acres) | a       40.0 11.02    
Contract sale price | $       $ 1,150 $ 220    
Culberson County              
Real Estate [Line Items]              
Approximate number of acres sold (acres) | a     80.0        
Contract sale price | $     $ 1,600        
El Paso County              
Real Estate [Line Items]              
Approximate number of acres sold (acres) | a   15.0          
Contract sale price | $   $ 270          
Reeves County              
Real Estate [Line Items]              
Approximate number of acres sold (acres) | a 31.8            
Contract sale price | $ $ 1,273