INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Deferred tax assets:
Developer deposits for contributions in aid of construction	$ 36,315	$ 34,353
Net operating loss carry-forward and tax credits	15,471	14,183
Pension liability	22,393	18,993
Income tax regulatory liability	9,459	13,893
Operating leases liabilities	3,488	3,778
Other	1,886	2,019
Total deferred tax assets	89,012	87,219
Deferred tax liabilities:
Property related basis and depreciation differences	520,012	482,124
Operating lease-right to use asset	3,420	3,722
Other	16,526	12,456
Total deferred tax liabilities	539,958	498,302
Net deferred tax liabilities	$ 450,946	$ 411,083