Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards.

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Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement.

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Percentage Of Alternative Minimum Tax

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INCOME TAXES - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	9 Months Ended		12 Months Ended
	Aug. 31, 2022	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2017
Income Taxes [Line Items]
Corporate federal income tax		21.00%	21.00%
Regulatory liability, expected flow back to customers						$ 47.1
Regulatory liability, expected pass back to ratepayers				$ 1.3
Net Operating Loss Carryforwards Utilized For Income Taxes					$ 2.9
Deferred tax assets, operating loss carryforwards, federal				7.3
Federal Tax Credits to Offset Current Taxes				1.7
Tax Adjustments and Settlements				$ 9.4
Percentage of alternate minimum tax	15.00%
Adjustment financial statement income	$ 1,000.0
Number of years used for calculating adjusted financial statement income	3 years
Gas Ratepayers \| Massachusetts And Maine [Member]
Income Taxes [Line Items]
Regulatory liability, expected flow back to customers		$ 11.5
Tax Year 2018
Income Taxes [Line Items]
Corporate federal income tax						21.00%	21.00%