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INCOME TAXES - Additional Information (Detail) - USD ($) $ in Millions | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2017
Income Taxes [Line Items] |  |  |  |  |
Corporate federal income tax | 21.00% | 21.00% |  |  |
Regulatory Liability | $ 73.5 | $ 57.8 | $ 64.0 |  |
Regulatory liability, expected flow back to customers |  |  |  |  | $ 47.1
State Taxes Credit to Offset Future Taxes |  |  | 1.6 |  |
Net Operating Loss Carryforwards Utilized For Income Taxes |  |  |  | $ 2.9 |
Offset future years income |  |  |  | $ 7.3 |
Deferred tax assets, operating loss carryforwards, federal |  |  | 6.6 |  |
Federal Tax Credits to Offset Current Taxes |  |  | 1.3 |  |
Gas Ratepayers | Massachusetts And Maine [Member] |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Regulatory liability, expected flow back to customers | 12.7 |  |  |  |
Income Tax Related Liabilities |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Regulatory Liability | $ 49.7 | $ 37.2 | $ 50.4 |  | $ 48.9
Tax Year 2018 |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Corporate federal income tax |  |  |  |  | 21.00%

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