Other Financial Information (Tables)

12 Months Ended

Dec. 31, 2024

Other Financial Information [Abstract]

Schedule of Noncash Operating Working Capital (Increase) Decrease

Supplemental Information to Statement of Cash Flows

(Thousands of dollars)	2024		2023		2022
Net (increase) decrease in operating working capital, excluding cash and cash equivalents:
(Increase) decrease in accounts receivable	$	71,081	$	47,151	$	(137,228)
(Increase) decrease in inventories	1,327		329		(1,534)
(Increase) decrease in prepaid expenses	1,192		(1,293)		(3,413)
Increase (decrease) in accounts payable and accrued liabilities ¹	3,287		(140,011)		69,854
Increase (decrease) in income taxes payable	(2,004)		(5,537)		6,593
Net decrease (increase) in non-cash operating working capital	$	74,883	$	(99,361)	$	(65,728)
Supplementary disclosures:
Cash income taxes paid, net of refunds	$	12,648	$	12,356	$	24,853
Interest paid, net of amounts capitalized of $11.4 million in 2024, $14.5 million in 2023 and $16.3 million in 2022	78,806		108,912		149,597
Non-cash investing activities:
Asset retirement costs capitalized	$	47,233	$	32,975	$	(21,147)
(Increase) decrease in capital expenditure accrual	(5,935)		17,517		(31,397)

1  Excludes receivable/payable balances relating to mark-to-market of derivative instruments.