Note 5 - Exploratory Well Costs (Details Textual)	9 Months Ended
Sep. 30, 2020
Capitalized Exploratory Well Costs, Maximum Term (Year)	1 year

Represents the maximum term for which all capitalized exploratory well costs have been capitalized.

No definition available.

Name:	hpk_CapitalizedExploratoryWellCostsMaximumTerm
Namespace Prefix:	hpk_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration