Environmental Matters - Additional Information (Detail) |
6 Months Ended |
|---|---|
|
Jun. 30, 2026
USD ($)
| |
| Environmental Restoration Costs | |
| Site Contingency [Line Items] | |
| Estimated Costs Accrued For Remediation | $ 5,900,000 |
| Fitchburg Manufactured Gas Plant Site [Member] | |
| Site Contingency [Line Items] | |
| Remediation costs | 3,700,000 |
| Fitchburg Manufactured Gas Plant Site [Member] | Environmental Restoration Costs | |
| Site Contingency [Line Items] | |
| Estimated Costs Accrued For Remediation | $ 300,000 |
| Environmental Remediation Expense, before Recovery, Statement of Income or Comprehensive Income [Extensible Enumeration] | Utilities Operating Expense |
| X | ||||||||||
- Definition Amount, before recovery, of expense for known and estimated future costs arising from requirement to perform environmental remediation. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Indicates line item in statement of income or comprehensive income that includes environmental remediation expense before recovery. Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef
|
| 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. Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef
|
| X | ||||||||||
- Definition Remediation costs No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|