Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Statement Of Comprehensive Income [Abstract]
Net earnings	$ 713,615	$ 341,724	$ 1,093,727	$ 719,372
Other comprehensive income:
Net unrealized loss on hedging derivatives, net of income taxes of ($1,100) and $0 for the second quarter of 2018 and 2017, respectively, and ($600) and ($1,000) for the first six months of 2018 and 2017, respectively	(3,647)	(71)	(4,399)	(1,706)
Reclassification adjustment for loss on settlement of hedging derivatives included in net income, net of income taxes of $100 and $0 for the second quarter of 2018 and 2017, respectively, and $100 and $300 for the first six months of 2018 and 2017, respectively	447	171	399	656
Foreign currency translation gain (loss), net of income taxes of $0 for the second quarter and first six months of 2018 and 2017	(43,466)	23,957	(37,351)	25,958
Net current-period other comprehensive income (loss)	(46,666)	24,057	(41,351)	24,908
Comprehensive income	666,949	365,781	1,052,376	744,280
Comprehensive income attributable to noncontrolling interests	(30,462)	(18,676)	(56,395)	(39,425)
Comprehensive income attributable to Nucor stockholders	$ 636,487	$ 347,105	$ 995,981	$ 704,855