Supplemental Gas and Oil Information (Unaudited) Average price per unit (Details)	12 Months Ended
	Dec. 31, 2020 $ / Mcf $ / bbl	Dec. 31, 2019 $ / Mcf $ / bbl	Dec. 31, 2018 $ / bbl $ / Mcf
Oil [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average benchmark price per unit | $ / bbl	39.57	55.51	65.56
Gas [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average benchmark price per unit | $ / Mcf	1.99	2.58	3.10