Financing Arrangements and Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Schedule of Long-term Debt

໿

	December 31,
(Thousands of dollars)	2019			2018
Notes payable
4.00% notes, due June 2022	$	260,251		500,000
4.45% notes, due December 2022 ¹	318,417			600,000
6.875% notes, due August 2024	550,000			550,000
5.75% notes, due August 2025	550,000			550,000
5.875% notes, due December 2027	550,000			—
7.05% notes, due May 2029	250,000			250,000
5.875% notes, due December 2042 ¹	350,000			350,000
Total notes payable	2,828,668			2,800,000
Unamortized debt issuance cost and discount on notes payable	(25,287		)	(23,627	)
Total notes payable, net of unamortized discount	2,803,381			2,776,373
Capitalized lease obligation, due through March 2029 ¹	—			8,613
Total debt including current maturities	2,803,381			2,784,986
Senior Unsecured Revolving Credit Facility	—			325,000
Current maturities ²	—			(668	)
Total long-term debt	$	2,803,381		3,109,318

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

² Capitalized lease obligation and current maturities relate to a finance lease in Brunei, which is classified as held for sale as of December 31, 2019 (see Note E).