Supplementary Information On Oil, NGL And Natural Gas Reserves (Summary of Proved Developed and Undeveloped Reserves) (Details)	Sep. 30, 2019 bbl Mcf	Sep. 30, 2018 bbl Mcf	Sep. 30, 2017 bbl Mcf
Oil [Member]
Reserve Quantities [Line Items]
Proved Developed Reserves (Volume)	1,863,096	2,334,587	2,201,528
Proved Undeveloped Reserves (Volume)	516,994	3,649,835	3,308,139
NGL [Member]
Reserve Quantities [Line Items]
Proved Developed Reserves (Volume)	1,747,242	2,085,706	1,768,425
Proved Undeveloped Reserves (Volume)	226,038	848,484	616,274
Natural Gas [Member]
Reserve Quantities [Line Items]
Proved Developed Reserves (Volume) | Mcf	67,713,193	83,151,954	87,861,043
Proved Undeveloped Reserves (Volume) | Mcf	12,560,713	36,910,082	33,334,077