Supplemental Gas and Oil Information (Unaudited) Future Development Costs (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Future Development Costs [Abstract]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs, Next Twelve Months	$ 202.6
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs, Year Two	289.1
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs, Year Three	$ 365.8

2013 - Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs, Next Twelve Months

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration