DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2025

Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]

Fair Value Measurements, Recurring and Nonrecurring

The following tables summarize, by level within the fair value hierarchy, our derivative and other assets and liabilities that were accounted for at fair value on a recurring basis at September 30, 2025 and December 31, 2024:

	September 30, 2025
	Level 1		Level 2		Netting (c)		Total
	(Thousands of dollars)
Assets:
United States treasury notes (b)	$	8,561	$	—	$	—	$	8,561
Corporate bonds (b)	—		15,767		—		15,767
Marketable equity securities (d)	2,567		—		—		2,567
Total assets	$	11,128	$	15,767	$	—	$	26,895
Liabilities:
Derivative instruments - swaps (a)	$	—	$	6,921	$	—	$	6,921

(a) The fair value is included in other current assets and other current liabilities in our consolidated balance sheets.

(b) The fair value is included in other current and noncurrent assets in our consolidated balance sheets.

(c) Our over-the-counter natural gas fixed-price swaps are presented on a net basis when the right of offset exists.

(d) The fair value is included in other current assets in our consolidated balance sheets.

	December 31, 2024
	Level 1		Level 2		Netting (c)		Total
	(Thousands of dollars)
Assets:
Derivative instruments - swaps (a)	$	—	$	25	$	(25)	$	—
United States treasury notes (b)	8,721		—		—		8,721
Corporate bonds (b)	—		13,171		—		13,171
Total assets	$	8,721	$	13,196	$	(25)	$	21,892
Liabilities:
Derivative instruments - swaps (a)	$	—	$	3,238	$	(25)	$	3,213

(a) The fair value is included in other current assets and other current liabilities in our consolidated balance sheets.

(b) The fair value is included in other current and noncurrent assets in our consolidated balance sheets.

(c) Our over-the-counter natural gas fixed-price swaps are presented on a net basis when the right of offset exists.