LONG-TERM DEBT - Annual Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Annual maturities of total debt adjusted for debt issuance costs, discounts and premiums
2024	$ 223,523
2025	238,845
2026	90,538
2027	92,421
2028	99,241
Thereafter	2,375,461
Total debt adjusted for debt issuance costs, discounts and premiums	3,120,029	$ 2,962,883
First Mortgage Bonds, Series 2014E-1, 3.70% due 2024 \| Secured Debt
Annual maturities of total debt adjusted for debt issuance costs, discounts and premiums
2024	128,000
Syndicated variable rate, SOFR-based term loan due 2025 \| Secured Debt
Annual maturities of total debt adjusted for debt issuance costs, discounts and premiums
2025	$ 150,000

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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