v3.26.1
LONG-TERM DEBT (Tables)
3 Months Ended
Mar. 31, 2026
Long-Term Debt, Unclassified [Abstract]  
Schedule of Long-Term Debt Instruments
The table below presents a summary of our long-term debt outstanding for the periods indicated:

March 31,December 31,
Interest Rate
20262025
(Thousands of dollars)
Senior Notes due:
April 20295.100%$550,000 $550,000 
May 20302.000%300,000 300,000 
September 20324.250%300,000 300,000 
February 20444.658%600,000 600,000 
November 20484.500%400,000 400,000 
Total Senior Notes2,150,000 2,150,000 
Unsecured Term Loan (a)4.480%250,000 250,000 
KGSS-I Securitized Utility Tariff Bonds5.486%242,496 257,852 
Unamortized discounts, net of premiums, on long-term debt (b)(3,883)(3,830)
Debt issuance costs (b)(18,298)(18,955)
Other8.000%1,207 1,211 
Total long-term debt, net2,621,522 2,636,278 
Less: current maturities of KGSS-I securitized utility tariff bonds, net31,404 30,566 
Less: current maturities of other long-term debt, net249,798 249,674 
Noncurrent portion of long-term debt, net$2,340,320 $2,356,038 
(a) Bears interest at a variable rate based on Term SOFR, initially set using the 6-month Term SOFR at closing. The interest rate resets at months six and twelve, each based on the prevailing 6-month Term SOFR and the 1-month Term SOFR, respectively.
(b) Includes issuance costs and discounts for the KGSS-I Securitized Utility Tariff Bonds of $4.1 million and $4.3 million, at March 31, 2026 and December 31, 2025, respectively.