Summary Of Significant Accounting Policies (Assets And Liabilities Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset commodity swap	$ 3,520
Assets	3,520
SARs liability	1,632	$ 146
Liabilities	1,632	146
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset commodity swap
Assets
SARs liability
Liabilities
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset commodity swap	3,520
Assets	3,520
SARs liability	1,632	146
Liabilities	1,632	146
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset commodity swap
Assets
SARs liability
Liabilities