v3.19.1

ASSET RETIREMENT OBLIGATION (Narrative) (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |
Undiscounted amount of asset retirement obligation | $ 59.5
Asset retirement obligation payments expected to be made | $ 6.6
Period in which no significant payments related to asset retirement obligation are expected (in years) | 5 years
Measurement Input, Risk Free Interest Rate [Member] | Minimum [Member] |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |
Credit risk free rate | 0.069
Measurement Input, Risk Free Interest Rate [Member] | Maximum [Member] |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |
Credit risk free rate | 0.097

X
- Definition Asset retirement obligation payments expected to be made in the next five years. + References No definition available. + Details
Name: | ipi_AssetRetirementObligationPaymentsExpectedToBeMade
Namespace Prefix: | ipi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The undiscounted amount of the asset retirement obligation. + References No definition available. + Details
Name: | ipi_AssetRetirementObligationUndiscountedAmount
Namespace Prefix: | ipi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Period in which payments are expected to take place that are associated with an asset retirement obligation. + References No definition available. + Details
Name: | ipi_PeriodInWhichPaymentsAreExpected
Namespace Prefix: | ipi_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- 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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of input used to measure long-term debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_LongTermDebtMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputRiskFreeInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |