Contingencies (Details Textual)  | 
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
| 
 Jun. 30, 2021  
USD ($) 
 | 
 Jun. 30, 2021  
USD ($) 
 | 
 Jul. 25, 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 | $ 8,200,000 | $ 6,900,000 | |
| BSEE [Member] | ||||
| Loss Contingency, Number of Claims Filed | 9 | |||
| Proposed Civil Penalties | $ 7,700,000 | |||
| Settlement Agreement, Annual Instalments, Value | 720,000 | $ 720,000 | ||
| Payment for Civil Penalty | $ 0 | 
| X | ||||||||||
- Definition Additional royalty payments made related to revised regulation interpretations referred to as unbundling. No definition available. 
  | 
| X | ||||||||||
- Definition Amount of bonds posted to appeal a decision made by the Interior Board of Land Appeals. No definition available. 
  | 
| X | ||||||||||
- Definition Cash collateral deposited related to bonds posted to appeal a decision made by the Interior Board of Land Appeals. No definition available. 
  | 
| X | ||||||||||
- Definition Represents the number of claims filed. No definition available. 
  | 
| X | ||||||||||
- Definition Payments made to government agencies for civil penalties related to incidents of non-compliance issued by the BSEE. No definition available. 
  | 
| X | ||||||||||
- Definition The amount of civil penalties proposed. No definition available. 
  | 
| X | ||||||||||
- Definition The value of annual installments to be paid in a settlement agreement. No definition available. 
  | 
| X | ||||||||||
- Details 
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