Organization and Accounting Policies (Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset commodity	$ 7,257	$ 636
Assets	7,257	636
SARs liability	742	2,638
SARs liability	34	852
Liabilities	776	3,490
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset commodity	7,257	636
Assets	7,257	636
SARs liability	742	2,638
SARs liability	34	852
Liabilities	$ 776	$ 3,490