Organization and Accounting Policies (Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SARs liability	$ 1,181	$ 2,289
Derivative liability - crude oil swaps	9,920
SARs liability		193
Liabilities	11,101	2,482
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SARs liability	1,181	2,289
Derivative liability - crude oil swaps	9,920
SARs liability		193
Liabilities	$ 11,101	$ 2,482