Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Statement Of Comprehensive Income [Abstract]
Net earnings		$ 836,028		$ 1,370,910		$ 2,481,084
Other comprehensive income (loss):
Net unrealized (loss) income on hedging derivatives, net of income taxes of $400, ($3,100) and ($300) for 2020, 2019 and 2018, respectively		2,084		(9,833)		(3,568)
Reclassification adjustment for (gain) loss on settlement of hedging derivatives included in net earnings, net of income taxes of $2,500, $700 and $0 for 2020, 2019 and 2018, respectively		7,216	[1]	2,333	[2]	(132)
Foreign currency translation (loss) gain, net of income taxes of $0 for 2020, 2019 and 2018		17,306		7,873		(47,133)
Adjustment to early retiree medical plan, net of income taxes of ($339), ($485) and $514 for 2020, 2019 and 2018, respectively		(1,213)		(1,148)		1,731
Reclassification adjustment for (gain) loss on early retiree medical plan included in net earnings, net of income taxes of $17, $49 and ($108) for 2020, 2019 and 2018, respectively		72	[1]	57	[2]	(350)
Liquidation of equity method investment in foreign joint venture, net of income taxes of $0 in 2020	[1]	158,640
Net current-period other comprehensive income (loss)		184,105		(718)		(49,452)
Comprehensive income		1,020,133		1,370,192		2,431,632
Comprehensive income attributable to noncontrolling interests		(114,558)		(99,767)		(120,317)
Comprehensive income attributable to Nucor stockholders		$ 905,575		$ 1,270,425		$ 2,311,315

[1] Includes $7,216 and $72 net-of-tax impact of accumulated other comprehensive income reclassifications into cost of products sold for net losses on commodity contracts and adjustment to early retiree medical plan, respectively. The tax impacts of these reclassifications were $2,500 and $17, respectively. Also includes a $158.6 million reclassification of cumulative foreign currency translation losses into losses and impairments of assets, of which there was no tax impact.

[2] Includes $2,333 and $57 net-of-tax impact of accumulated other comprehensive income reclassifications into cost of products sold for net losses on commodity contracts and adjustment to early retiree medical plan, respectively. The tax impacts of these reclassifications were $700 and $49, respectively.