INCOME TAXES - Reconciliation of Statutory Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Amount
U.S. federal statutory tax rate	$ 30,860	$ 48,840	$ 9,365
State and local income tax, net of federal (national) income tax effect	10,257	16,234	3,718
TCJA refund	(11,638)	(11,508)	(11,618)
Effect of regulatory treatment of fixed asset differences	(9,539)	(11,053)	(9,478)
AFUDC equity	(2,363)	(1,931)	(1,553)
Investment tax credits	(71)	(71)	(74)
Change in valuation allowances	0
Stock-based compensation	991	962	677
Change in unrecognized tax benefits	331
Other adjustments	278
Other		1,016	2,182
Total income tax	$ 19,106	$ 42,489	$ (6,781)
Percent
U.S. federal statutory tax rate	21.00%
State and local income tax, net of federal (national) income tax effect	7.00%
TCJA refund	(7.90%)
Effect of regulatory treatment of fixed asset differences	(6.50%)
AFUDC equity	(1.60%)
Investment tax credits	(0.10%)
Change in valuation allowances	0.00%
Stock-based compensation	0.70%
Change in unrecognized tax benefits	0.20%
Other adjustments	0.20%
Effective tax rate	13.00%