Fair Value Measurements (Schedule Of Quantitative Information About Unobservable Inputs) (Details) - Natural Gas [Member] - Level 3 [Member] - Three-way collar [Member] $ in Thousands	6 Months Ended
Jun. 30, 2020 USD ($) $ / Unit
Derivative fair value \| $	$ 843
Unobservable Input	Forward commodity price curve
Minimum [Member]
Forward commodity price curve	0
Maximum [Member]
Forward commodity price curve	0.75

Fair value of the assets less the liabilities of a derivative or group of derivatives.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13433-108611

Name:	us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant