Annual report pursuant to Section 13 and 15(d)

RELATED???PARTY TRANSACTIONS (Details)

v3.10.0.1
RELATED‑PARTY TRANSACTIONS (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2018
USD ($)
property
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Related Party Transaction [Line Items]      
Payable to related parties $ 10 $ 20 $ 0
Receivable from related parties $ 0 0 40
Related party leasing      
Related Party Transaction [Line Items]      
Lease term 5 years    
Extension option term 5 years    
Expenses with related party $ 100    
Number of properties adjacent to corporate office subject to leases | property 5    
Related party leasing | Property 1      
Related Party Transaction [Line Items]      
Expenses with related party $ 30    
Related party leasing | Property 2      
Related Party Transaction [Line Items]      
Expenses with related party 30    
Related party leasing | Property 3      
Related Party Transaction [Line Items]      
Expenses with related party 100    
Related party leasing | Property 4      
Related Party Transaction [Line Items]      
Expenses with related party 100    
Related party leasing | Property 5      
Related Party Transaction [Line Items]      
Expenses with related party 200    
Related party transportation services      
Related Party Transaction [Line Items]      
Expenses with related party 400 300 200
Related party equipment rental      
Related Party Transaction [Line Items]      
Expenses with related party $ 200 $ 200 $ 200