Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130533-203044

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173487&loc=SL51747714-108306

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130531-203044

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130549-203045

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_DisaggregationOfRevenueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of other operating income, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_OtherOperatingIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 32
-Paragraph 2A
-URI http://asc.fasb.org/extlink&oid=82859839&loc=SL82860478-203043

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130543-203045

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130539-203045

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130545-203045

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis=us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=hk_OilNaturalGasAndNaturalGasLiquidsSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=us-gaap_OilReservesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=us-gaap_NaturalGasReservesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=us-gaap_NaturalGasLiquidsReservesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=hk_AccountsReceivableNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

OPERATING REVENUES - Revenue Recognition (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 09, 2016	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of operating revenue
Other	$ 802		$ 1,080	$ 2,128
Total operating revenues	153,362		226,609	377,965
Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Other	802			2,128
Total operating revenues	153,362			377,965
Total oil, natural gas and natural gas liquids sales
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	152,560		225,529	375,837
Total oil, natural gas and natural gas liquids sales \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	152,560			375,837
Oil
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	139,786		199,601	340,674
Oil \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	139,786			340,674
Natural gas
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	6,756		6,791	16,194
Natural gas \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	6,756			16,194
Natural gas liquids
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	6,018		19,137	18,969
Natural gas liquids \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales	$ 6,018			18,969
Accounts receivable
Disaggregation of operating revenue
Due from contracts with customers			$ 26,400	$ 24,100
Predecessor
Disaggregation of operating revenue
Other		$ 1,339
Total operating revenues		266,843
Predecessor \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Other		1,339
Total operating revenues		266,843
Predecessor \| Total oil, natural gas and natural gas liquids sales
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		265,504
Predecessor \| Total oil, natural gas and natural gas liquids sales \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		265,504
Predecessor \| Oil
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		248,064
Predecessor \| Oil \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		248,064
Predecessor \| Natural gas
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		9,511
Predecessor \| Natural gas \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		9,511
Predecessor \| Natural gas liquids
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		7,929
Predecessor \| Natural gas liquids \| Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of operating revenue
Total oil, natural gas and natural gas liquids sales		$ 7,929