Financing Arrangements and Debt (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Long-term Debt

Long-term debt for the respective periods presented consisted of the following:

	December 31,
(Thousands of dollars)	2023		2022
Notes payable
5.75% notes, due August 2025	$	–	$	248,675
5.875% notes, due December 2027	443,249		543,249
6.375% notes, due July 2028	372,226		451,934
7.05% notes, due May 2029	179,708		250,000
5.875% notes, due December 2042 ¹	339,761		339,761
Total notes payable	1,334,944		1,833,619
Unamortized debt issuance cost and discount on notes payable	(10,107)		(15,324)
Total notes payable, net of unamortized discount	1,324,837		1,818,295
Capitalized lease obligation, due through March 2029	4,238		4,844
Total debt including current maturities	1,329,075		1,823,139
Current maturities	(723)		(687)
Total long-term debt	$	1,328,352	$	1,822,452

1 Coupon rate may fluctuate 25 basis points if rating is periodically downgraded or upgraded by S&P and Moody’s.