Cash Unit Based Compensation Awards

No definition available.

Name:	hpr_CashUnitBasedCompensationAwards
Namespace Prefix:	hpr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Non-Cash Stock Based Compensation Equity Awards

+ References

No definition available.

+ Details

Name:	hpr_NonCashStockBasedCompensationEquityAwards
Namespace Prefix:	hpr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Stock Based Compensation [Line Items]

+ References

No definition available.

+ Details

Name:	hpr_StockBasedCompensationLineItems
Namespace Prefix:	hpr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for deferred compensation arrangements payable after one year (or the normal operating cycle, if longer). Represents currently earned compensation under cash arrangements (such as a profit-sharing plan, rabbi trust, and employee contract--excluding equity-based arrangements) that is not actually paid until a later date.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationCashbasedArrangementsLiabilityClassifiedNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AwardTypeAxis=hpr_NonvestedEquitySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=hpr_NonvestedEquityCommonStockUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=hpr_NonvestedPerformanceCashUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Equity Incentive Compensation Plans and Other Long-term Incentive Programs - Non-Cash Stock-Based Compensation Cost Related to Equity Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Stock Based Compensation [Line Items]
Non-cash stock-based compensation equity awards	$ 971	$ 2,145	$ 2,977	$ 7,163
Unrecognized compensation expense	4,000		$ 4,000
Unrecognized compensation expense, recognition period			1 year 7 months 6 days
Nonvested Equity Shares
Stock Based Compensation [Line Items]
Non-cash stock-based compensation equity awards	996	1,992	$ 3,296	5,321
Nonvested Equity Common Stock Units
Stock Based Compensation [Line Items]
Non-cash stock-based compensation equity awards	30	283	512	895
Nonvested Performance Cash Units
Stock Based Compensation [Line Items]
Nonvested performance cash units	(55)	$ (130)	(831)	$ 947
Nonvested performance-based cash units accounted for as liability awards	$ 300		$ 300		$ 1,200