Annual report pursuant to Section 13 and 15(d)

Note 17 - Contingencies (Details Textual)

v3.20.4
Note 17 - Contingencies (Details Textual)
 12 Months Ended
May 31, 2017
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Jan. 31, 2020
USD ($)
Jul. 25, 2017
USD ($)
Jun. 30, 2017
USD ($)
Dec. 31, 2010
USD ($)
Additional Royalty Due to Disallowed Deductions               $ 4,700,000
Bonds Posted to Appeal IBLA Decision           $ 7,200,000    
Collateral for Bonds Posted Related to Appeal with IBLA   $ 8,200,000     $ 6,900,000 $ 6,900,000    
Minerals Management Service Royalties [Member] | Maximum [Member]                
Claim Value, Liability Reserve     $ 250,000,000,000          
BSEE [Member]                
Payment for Civil Penalty   $ 0 0          
Loss Contingency, Number of Claims Filed   9            
Proposed Civil Penalties   $ 7,700,000            
Settlement Agreement, Annual Instalments, Value   720,000            
ONRR Unbundling Initiative [Member]                
Payments for Royalties   $ 200,000 400,000 $ 600,000        
Judicial Ruling [Member] | Apache Corporation [Member]                
Loss Contingency, Damages Awarded, Value $ 49,500,000              
Escrow Deposit             $ 49,500,000  
Judicial Ruling [Member] | Apache Corporation [Member] | Interest Expense [Member]                
Interest Income, Litigation     $ 1,900,000          
Judicial Ruling [Member] | Apache Corporation [Member] | Other Noncurrent Assets [Member]                
Loss Contingency Accrual, Ending Balance       49,500,000        
Judicial Ruling [Member] | Apache Corporation [Member] | Other Noncurrent Liabilities [Member]                
Loss Contingency Accrual, Ending Balance       $ 49,500,000