| **Commitments and Contingent Liabilities (Details) $ in Millions** | 9 Months Ended |
|--------------------------------------------------------------------|----------------|
||
| **Site Contingency [Line Items]**                                  |           |
| Accrual For Environmental Loss Contingencies Gross                 | $ 1.0          |
| **Long-term Purchase Commitment [Line Items]**                     |           |
| Number Of Regulatory Commissions | regulatory_commission           | 3              |
| Letter Of Credit                                                   |           |
| **Guarantor Obligations [Line Items]**                             |           |
| Total contingent obligation                                        | $ 1.7          |
| Surety Bond                                                        |           |
| **Guarantor Obligations [Line Items]**                             |           |
| Total contingent obligation                                        | 6.5            |
| Manufactured Gas Plant Sites                                       |           |
| **Site Contingency [Line Items]**                                  |           |
| Accrual For Environmental Loss Contingencies Gross                 | 0.9            |
| Other Environmental Remediation Sites                              |           |
| **Site Contingency [Line Items]**                                  |           |
| Accrual For Environmental Loss Contingencies Gross                 | $ 0.1          |
| Pipeline And Storage Capacity Contacts | Maximum                   |           |
| **Long-term Purchase Commitment [Line Items]**                     |           |
| Long term purchase commitment time period                          | 20 years       |
| Reservation Fees Under Gas Supply Contracts | Maximum              |           |
| **Long-term Purchase Commitment [Line Items]**                     |           |
| Long term purchase commitment time period                          | 1 year         |
| Gas Supply Purchase Commitments | Maximum                          |           |
| **Long-term Purchase Commitment [Line Items]**                     |           |
| Long term purchase commitment time period                          | 15 years       |
| Telecommunications And Technology Outsourcing Contracts | Maximum  |           |
| **Long-term Purchase Commitment [Line Items]**                     |           |
| Long term purchase commitment time period                          | 5 years        |

| X                                                                                                                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total number of regulatory commission that have jurisdiction over the service areas in which the company operates.
+ References
No definition available.
+ Details**Name:**pny_NumberOfRegulatoryCommissions**Namespace Prefix:**pny_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Undiscounted amount of the accrual for environmental loss contingencies.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q1) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859
+ Details**Name:**us-gaap_AccrualForEnvironmentalLossContingenciesGross**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| 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_GuaranteeObligationsLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248
+ Details**Name:**us-gaap_GuaranteeObligationsMaximumExposure**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| 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_LongTermPurchaseCommitmentLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Period covered by the long-term purchase commitment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
No definition available.
+ Details**Name:**us-gaap_LongtermPurchaseCommitmentPeriod**Namespace Prefix:**us-gaap_**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_SiteContingencyLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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