Supplementary Information On Oil, NGL And Natural Gas Reserves (Summary of Proved Undeveloped Reserves) (Details)	12 Months Ended
	Sep. 30, 2019 Mcfe
Extractive Industries [Abstract]
Beginning proved undeveloped reserves	63,899,996
Proved undeveloped reserves transferred to proved developed	(1,763,402)
Revisions	(48,404,716)
Extensions and discoveries	4,679,986
Sales	(1,648,780)
Purchases	255,821
Ending proved undeveloped reserves	17,018,905