INCOME TAXES - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Aug. 31, 2022	Mar. 31, 2024	Mar. 31, 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					$ 1.4
Current Federal Tax Expense (Benefit)					$ 0.2
Deferred tax assets, operating loss carryforwards, federal				4.4
Federal Tax Credits to Offset Current Taxes				$ 1.7
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		$ 10.1
Tax Year 2018
Income Taxes [Line Items]
Corporate federal income tax						21.00%	21.00%