CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (unaudited) - USD ($) $ in Thousands	Total	Murphy Shareholders’ Equity	Cumulative Preferred Stock	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interest
Balance at beginning of period at Dec. 31, 2019				$ 195,089	$ 949,445	$ 6,614,304	$ (574,161)	$ (1,717,217)	$ 337,151
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, including income tax benefits				12	(156)
Restricted stock transactions and other					(33,649)
Share-based compensation					20,678
Net income (loss)	$ (976,841)					(976,841)			(122,869)
Cash dividends						(76,790)
Foreign currency translation gain (loss), net of income taxes	(39,520)						(39,520)
Retirement and postretirement benefit plans, net of income taxes							(45,219)
Deferred loss on interest rate hedges reclassified to interest expense, net of income taxes	905						905
Awarded restricted stock, net of forfeitures								26,556
Distributions to noncontrolling interest owners									(43,673)
Balance at end of period at Sep. 30, 2020	4,514,045	$ 4,343,436	$ 0	195,101	936,318	5,560,673	(657,995)	(1,690,661)	170,609
Balance at beginning of period at Jun. 30, 2020				195,101	931,429	5,823,426	(690,341)	(1,691,070)	204,937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock transactions and other					(409)
Share-based compensation					5,298
Net income (loss)	(243,553)					(243,553)			(23,055)
Cash dividends						(19,200)
Foreign currency translation gain (loss), net of income taxes	28,323						28,323
Retirement and postretirement benefit plans, net of income taxes							3,726
Deferred loss on interest rate hedges reclassified to interest expense, net of income taxes	297						297
Awarded restricted stock, net of forfeitures								409
Distributions to noncontrolling interest owners									(11,273)
Balance at end of period at Sep. 30, 2020	4,514,045	4,343,436	0	195,101	936,318	5,560,673	(657,995)	(1,690,661)	170,609
Balance at beginning of period at Dec. 31, 2020	4,394,147			195,101	941,692	5,369,538	(601,333)	(1,690,661)	179,810
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, including income tax benefits					(661)			549
Restricted stock transactions and other					(38,749)
Share-based compensation					18,945
Net income (loss)	(242,064)					(242,064)			85,509
Cash dividends						(57,896)
Foreign currency translation gain (loss), net of income taxes	6,534						6,534
Retirement and postretirement benefit plans, net of income taxes							12,935
Deferred loss on interest rate hedges reclassified to interest expense, net of income taxes	1,690						1,690
Awarded restricted stock, net of forfeitures								33,888
Distributions to noncontrolling interest owners									(100,880)
Balance at end of period at Sep. 30, 2021	4,113,947	3,949,508	0	195,101	921,227	5,069,578	(580,174)	(1,656,224)	164,439
Balance at beginning of period at Jun. 30, 2021				195,101	915,181	4,980,428	(553,519)	(1,656,591)	161,228
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, including income tax benefits					(35)			24
Restricted stock transactions and other					(402)
Share-based compensation					6,483
Net income (loss)	108,456					108,456			28,853
Cash dividends						(19,306)
Foreign currency translation gain (loss), net of income taxes	(31,308)						(31,308)
Retirement and postretirement benefit plans, net of income taxes							4,653
Deferred loss on interest rate hedges reclassified to interest expense, net of income taxes	0
Awarded restricted stock, net of forfeitures								343
Distributions to noncontrolling interest owners									(25,642)
Balance at end of period at Sep. 30, 2021	$ 4,113,947	$ 3,949,508	$ 0	$ 195,101	$ 921,227	$ 5,069,578	$ (580,174)	$ (1,656,224)	$ 164,439