XML 97 R82.htm IDEA: XBRL DOCUMENT
v3.8.0.1

GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Debt (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Sep. 30, 2017 | Mar. 19, 2015
Financial Information |  |
Percentage ownership of subsidiary | 100.00% |
Unsecured senior notes issued March 19, 2015 |  |
Financial Information |  |
Debt issued | $ 500.0 | $ 500.0
Issuer Subsidiary | Unsecured senior notes issued March 19, 2015 |  |
Financial Information |  |
Debt issued | $ 500.0 |

X
- Definition NA + References No definition available. + Details
Name: | hp_ConsolidatedCondensedFinancialInformationAbstract
Namespace Prefix: | hp_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of subsidiary's or equity method investee's stock owned by parent immediately after all stock transactions. + References No definition available. + Details
Name: | us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hp_UnsecuredSeniorNotesIssued2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConsolidatedEntitiesAxis=us-gaap_SubsidiaryIssuerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |