Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Statement Of Comprehensive Income [Abstract]
Net earnings	$ 706,287	$ 266,105	$ 1,800,014	$ 985,477
Other comprehensive income (loss):
Net unrealized income (loss) on hedging derivatives, net of income taxes of $(400) and $300 for the third quarter of 2018 and 2017, respectively, and $(1,000) and $(700) for the first nine months of 2018 and 2017, respectively	(1,393)	405	(5,792)	(1,301)
Reclassification adjustment for loss on settlement of hedging derivatives included in net income, net of income taxes of $100 and $0 for the third quarter of 2018 and 2017, respectively, and $200 and $300 for the first nine months of 2018 and 2017, respectively	193	195	592	851
Foreign currency translation gain (loss), net of income taxes of $0 for the third quarter of 2018 and 2017, and $0 for the first nine months of 2018 and 2017	22,625	74,479	(14,726)	100,437
Net current-period other comprehensive income (loss)	21,425	75,079	(19,926)	99,987
Comprehensive income	727,712	341,184	1,780,088	1,085,464
Comprehensive income attributable to noncontrolling interests	(29,631)	(11,255)	(86,026)	(50,680)
Comprehensive income attributable to Nucor stockholders	$ 698,081	$ 329,929	$ 1,694,062	$ 1,034,784