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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%