Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions (Details)

v3.10.0.1
Related-Party Transactions (Details)
9 Months Ended
Sep. 30, 2018
USD ($)
property
Sep. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Related Party Transaction [Line Items]      
Operating leases, year two $ 782,000    
Operating leases, year three 721,000    
Operating leases, year four 721,000    
Payable to related parties 0   $ 20,000
Receivable from related parties $ 0   $ 0
Related party leasing      
Related Party Transaction [Line Items]      
Number of properties adjacent to corporate office subject to leases | property 5    
Related party transportation services      
Related Party Transaction [Line Items]      
Expenses with related party $ 300,000 $ 200,000  
Related party equipment rental      
Related Party Transaction [Line Items]      
Expenses with related party $ 100,000 $ 100,000  
Corporate offices | Related party leasing      
Related Party Transaction [Line Items]      
Lease term 5 years    
Extension option term 5 years    
Operating leases $ 100,000    
Property 1 | Related party leasing      
Related Party Transaction [Line Items]      
Operating leases 30,000    
Operating leases, year two 30,000    
Operating leases, year three 100,000    
Operating leases, year four 100,000    
Operating leases, year five $ 200,000