Supplemental Quarterly Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenue from contracts with customers	$ 440,100	$ 425,300	$ 285,700	$ 600,600	$ 757,000	$ 750,300	$ 680,400	$ 629,400	$ 1,751,709	$ 2,817,111	$ 1,806,473
Income (loss) from continuing operations before income taxes	(207,300)	(328,400)	(417,900)	(595,400)	(115,300)	177,100	107,900	33,700	(1,549,035)	203,498	43,002
Income (loss) from continuing operations	(162,500)	(265,900)	(323,100)	(503,800)	(91,300)	158,300	98,800	22,900	(1,255,294)	188,815	169,138
Net income (loss) including noncontrolling interest	(162,700)	(266,600)	(324,400)	(508,700)	(54,400)	1,111,700	123,200	72,800	(1,262,445)	1,253,302	419,486	[1]
Net income (loss) attributable to Murphy	$ (171,900)	$ (243,500)	$ (317,200)	$ (416,100)	$ (71,700)	$ 1,089,000	$ 92,300	$ 40,200	$ (1,148,777)	$ 1,149,732	$ 411,094
Income (loss) from continuing operations per Common share
Basic (in USD per share)	$ (1.11)	$ (1.58)	$ (2.05)	$ (2.68)	$ (0.71)	$ 0.85	$ 0.40	$ (0.06)	$ (7.43)	$ 0.52	$ 0.92
Diluted (in USD per share)	(1.11)	(1.58)	(2.05)	(2.68)	(0.70)	0.84	0.40	(0.06)	(7.43)	0.52	0.92
Net income (loss) per Common share
Basic (in USD per share)	(1.11)	(1.59)	(2.06)	(2.71)	(0.71)	6.79	0.55	0.23	(7.48)	7.01	2.38
Diluted (in USD per share)	(1.11)	(1.59)	(2.06)	(2.71)	(0.47)	6.76	0.54	0.23	(7.48)	6.98	2.36
Cash dividend per Common share (in USD per share)	$ 0.125	$ 0.125	$ 0.125	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.625	$ 1.00	$ 1.00
Impairment of assets									$ 1,206,284	$ 0	$ 20,000	[1]

[1] Reclassified to conform with current presentation