CONTINGENCIES AND COMMITMENTS - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Operating leases
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other	Other
Other assets: Other	$ 12,223	$ 13,301
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other accrued liabilities	Other accrued liabilities
Other accrued liabilities	$ 1,213	$ 1,218
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities	Other long-term liabilities
Other long-term liabilities	$ 11,254	$ 12,285
Total operating lease liabilities	12,467	13,503
Finance leases
Depreciable plant and equipment	18,760	18,761
Accumulated depreciation and amortization	(16,658)	(16,102)
Net utility plant	$ 2,102	$ 2,659
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current maturities of long-term debt, net	Current maturities of long-term debt, net
Current maturities of long-term debt, net	$ 1,913	$ 2,099
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt, net	Long-term debt, net
Long-term debt, net	$ 0	$ 688
Total finance lease liabilities	$ 1,913	$ 2,787
Weighted average remaining lease term
Operating leases	96 months	100 months
Finance leases	11 months	17 months
Weighted average discount rate
Operating leases	3.90%	3.80%
Finance leases	3.70%	5.60%