Supplementary Information On Natural Gas, Oil And NGL Reserves (Summary of Proved Developed and Undeveloped Reserves) (Details)	Sep. 30, 2020 bbl Mcf	Sep. 30, 2019 bbl Mcf	Sep. 30, 2018 bbl Mcf
Natural Gas [Member]
Reserve Quantities [Line Items]
Proved Developed Reserves (Volume) | Mcf	40,924,083	67,713,193	83,151,954
Proved Undeveloped Reserves (Volume) | Mcf	1,448,690	12,560,713	36,910,082
Oil [Member]
Reserve Quantities [Line Items]
Proved Developed Reserves (Volume)	1,148,989	1,863,096	2,334,587
Proved Undeveloped Reserves (Volume)	184,668	516,994	3,649,835
NGL [Member]
Reserve Quantities [Line Items]
Proved Developed Reserves (Volume)	1,135,864	1,747,242	2,085,706
Proved Undeveloped Reserves (Volume)	83,993	226,038	848,484