Commitments And Contingencies (Narrative) (Details)	6 Months Ended
	Jun. 30, 2017 $ / bbl	Sep. 30, 2015 USD ($)
Loss Contingencies [Line Items]
Period of trailing average of WTI	30 days
Incidence Of Non-Compliance [Member]
Loss Contingencies [Line Items]
Maximum potential loss | $		$ 386,000
Minimum [Member]
Loss Contingencies [Line Items]
Compensation reduction until WTI posting	70
Compensation reimbursement at WTI posting	85