SUPPLEMENTAL OIL AND GAS INFORMATION (UNAUDITED) - General Disclosures (Details)	12 Months Ended
Jun. 30, 2017
SUPPLEMENTAL OIL AND GAS INFORMATION (UNAUDITED)
Estimated future net cash flows, discount rate (as a percent)	10.00%

Represents the rate of discount used to estimate future net cash flows of the entity.

No definition available.

Name:	hdy_EstimatedFutureCashFlowRateOfDiscount
Namespace Prefix:	hdy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration