Annual report pursuant to Section 13 and 15(d)

Leases (Lease Cost on Consolidated Statement of Operations) (Details)

v3.20.4
Leases (Lease Cost on Consolidated Statement of Operations) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Lease Costs [Line Items]    
Total lease expense $ 28,793 $ 28,236
Lease costs capitalized 1,171 1,134
Total lease costs 29,964 29,370
Production Expense [Member]    
Lease Costs [Line Items]    
Total lease expense 7,904 7,859
General and Administrative Expense [Member]    
Lease Costs [Line Items]    
Total lease expense 197 196
Lease Costs Billed To Joint Venture Owners [Member]    
Lease Costs [Line Items]    
Total lease expense $ 20,692 $ 20,181