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Supplemental Disclosures about Oil and Natural Gas Producing Properties (unaudited) - Schedule of NYMEX Prices Used in Determining Future Cash Flows (Details)	12 Months Ended
	Jun. 30, 2018 $ / bbl $ / MMBtu	Jun. 30, 2017 $ / bbl $ / MMBtu	Jun. 30, 2016 $ / bbl $ / MMBtu
Oil (per barrel)
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Commodity Prices Used in Determining Future Cash Flows | $ / bbl	57.50	48.85	42.91
Gas (per million BTU)
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Commodity Prices Used in Determining Future Cash Flows | $ / MMBtu	0	0	0

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- Definition

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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