Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 28, 2019		Sep. 29, 2018		Sep. 28, 2019		Sep. 29, 2018
Statement Of Comprehensive Income [Abstract]
Net earnings	$ 293,587		$ 706,287		$ 1,236,657		$ 1,800,014
Other comprehensive income:
Net unrealized loss on hedging derivatives, net of income taxes of $(1,000) and $(400) for the third quarter of 2019 and 2018, respectively, and $(2,500) and $(1,000) for the first nine months of 2019 and 2018, respectively	(3,315)		(1,393)		(7,801)		(5,792)
Reclassification adjustment for settlement of hedging derivatives included in net income, net of income taxes of $500 and $100 for the third quarter of 2019 and 2018, respectively, and $500 and $200 for the first nine months of 2019 and 2018, respectively	1,615	[1]	193	[2]	1,501	[1]	592	[2]
Foreign currency translation (loss) gain, net of income taxes of $0 for the third quarter and first nine months of 2019 and 2018	(14,306)		22,625		(5,219)		(14,726)
Net current-period other comprehensive income (loss)	(16,006)		21,425		(11,519)		(19,926)
Comprehensive income	277,581		727,712		1,225,138		1,780,088
Comprehensive income attributable to noncontrolling interests	(18,556)		(29,631)		(73,337)		(86,026)
Comprehensive income attributable to Nucor stockholders	$ 259,025		$ 698,081		$ 1,151,801		$ 1,694,062

[1] Includes $1,615 and $1,501 of accumulated other comprehensive income (loss) reclassifications into cost of products sold for net losses on commodity contracts in the third quarter and first nine months of 2019, respectively. The tax impact of those reclassifications was $500 in both the third quarter and first nine months of 2019.

[2] Includes $193 and $592 of accumulated other comprehensive income (loss) reclassifications into cost of products sold for net losses on commodity contracts in the third quarter and first nine months of 2018, respectively. The tax impact of those reclassifications was $100 and $200 in the third quarter and first nine months of 2018, respectively.