Represents the minimum depth to be seabed during the exploration of well to satisfy the work requirement.

No definition available.

Name:	hdy_ExplorationOfWellMinimumDepthToBeSeabedToSatisfyWorkRequirement
Namespace Prefix:	hdy_
Data Type:	num:lengthItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage interest in the investment of an oil and gas property.

+ References

No definition available.

+ Details

Name:	hdy_OilAndGasPropertiesOwnershipInterest
Namespace Prefix:	hdy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the interest of the entity sold in the investment in oil and gas properties managed by the entity.

+ References

No definition available.

+ Details

Name:	hdy_OilAndGasPropertiesOwnershipInterestSold
Namespace Prefix:	hdy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the notice period to extend the second exploration period.

+ References

No definition available.

+ Details

Name:	hdy_SecondExplorationPeriodExtensionOfTermNoticePeriod
Namespace Prefix:	hdy_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the extension term of the second exploration period to allow the completion of any discovery made.

+ References

No definition available.

+ Details

Name:	hdy_SecondExplorationPeriodExtensionOfTermToAllowCompletionOfAppraisal
Namespace Prefix:	hdy_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the extension term of the second exploration period to allow the completion of a well in process.

+ References

No definition available.

+ Details

Name:	hdy_SecondExplorationPeriodExtensionOfTermToAllowCompletionOfWellInProcess
Namespace Prefix:	hdy_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	hdy_StatusOfBusinessAbstract
Namespace Prefix:	hdy_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the threshold gross expenditure cap related to future costs associated with well to be paid by the entity in the sale of an investment.

+ References

No definition available.

+ Details

Name:	hdy_ThresholdGrossExpenditureCapForDeterminationOfBearingPortionOfShareOfCost
Namespace Prefix:	hdy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=hdy_GuineaConcessionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=hdy_TullowGuineaLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=hdy_DanaPetroleumEAndPLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=hdy_TullowGuineaLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - Status of Our Business - Oil and Gas Properties (Details) - Guinea concession $ in Millions	6 Months Ended
	Dec. 31, 2015 m	Dec. 31, 2012 USD ($)	Dec. 30, 2012
Status of our Business
Ownership interest (as a percent)	37.00%	37.00%	77.00%
Extension term of the second exploration period, notice period	2 years
Extension term of the second exploration period to allow completion of well in process	1 year
Extension term of the second exploration period to allow completion of appraisal	2 years
Minimum depth to be seabed \| m	2,500
Tullow Guinea Ltd
Status of our Business
Ownership interest sold (as a percent)		40.00%
Threshold gross expenditure cap for well to be paid by the entity \| $		$ 100
Dana
Status of our Business
Ownership interest (as a percent)	23.00%
Tullow Guinea Ltd
Status of our Business
Ownership interest (as a percent)	40.00%