Annual report pursuant to Section 13 and 15(d)

Note 18 - Contingencies (Details Textual)

v3.19.3.a.u2
Note 18 - Contingencies (Details Textual)
$ in Thousands
 12 Months Ended
May 31, 2017
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Jul. 25, 2017
USD ($)
Jun. 30, 2017
USD ($)
Jan. 27, 2017
USD ($)
Dec. 31, 2010
USD ($)
Escrow Deposit   $ 49,500          
Additional Royalty Due to Disallowed Deductions             $ 4,700 $ 4,700
Bonds Posted to Appeal IBLA Decision         $ 7,200      
Collateral for Bonds Posted Related to Appeal with IBLA         $ 6,900      
Incremental Payments for Royalties Related to Unbundling   400 600 $ 1,600        
Minerals Management Service ("MMS") [Member]                
Loss Contingency Accrual, Ending Balance   250            
BSEE [Member]                
Loss Contingency Accrual, Ending Balance   3,500 3,500          
Payment for Civil Penalty   $ 0 0          
Loss Contingency, Number of Claims Filed   9            
Proposed Civil Penalties   $ 7,700            
Other Noncurrent Liabilities [Member]                
Loss Contingency Accrual, Ending Balance   49,500          
Apache Corporation [Member] | Judicial Ruling [Member]                
Loss Contingency, Damages Awarded, Value $ 49,500              
Escrow Deposit           $ 49,500    
Apache Corporation [Member] | Judicial Ruling [Member] | Interest Expense [Member]                
Interest Income, Litigation   $ 1,900            
Apache Corporation [Member] | Judicial Ruling [Member] | Other Noncurrent Assets [Member]                
Loss Contingency Accrual, Ending Balance     49,500          
Apache Corporation [Member] | Judicial Ruling [Member] | Other Noncurrent Liabilities [Member]                
Loss Contingency Accrual, Ending Balance     $ 49,500