Disposal Group, Not Discontinued Operation, Subsidiary Or Equity Method Investee, Ownership Interest Sold

No definition available.

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Namespace Prefix:	hp_
Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Number Of International Locations

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Amount of gain (loss) on sale or disposal of equity in securities of subsidiaries or equity method investee.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(b)(9)(a))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(13)(g))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(b)(7)(c))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(3)(a))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

+ Details

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

- Definition

The cash inflow associated with the deconsolidation of a previously consolidated subsidiary or the sale of investment in consolidated subsidiaries (generally greater than 50 percent).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
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- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=hp_TerraViciDrillingSolutionsInc.TerraViciMember
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NATURE OF OPERATIONS (Details) $ in Thousands	1 Months Ended	12 Months Ended
NATURE OF OPERATIONS (Details) $ in Thousands	Dec. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) location	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of international locations \| location		4
Proceeds from sale of subsidiary		$ 15,056	$ 0	$ 0
Gain on sale of subsidiary		$ 14,963	$ 0	$ 0
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| TerraVici
Segment Reporting Information [Line Items]
Percent of outstanding capital stock transferred to the purchaser	100.00%
Proceeds from sale of subsidiary	$ 15,100
Gain on sale of subsidiary	$ 15,000