Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Income Statement [Abstract]
Net sales	$ 5,568,419	$ 4,815,179
Costs, expenses and other:
Cost of products sold	4,842,013	4,054,929
Marketing, administrative and other expenses	182,960	176,426
Equity in earnings of unconsolidated affiliates	(9,580)	(8,756)
Interest expense, net	37,114	43,605
Costs, expenses and other, total	5,052,507	4,266,204
Earnings before income taxes and noncontrolling interests	515,912	548,975
Provision for income taxes	135,800	171,327
Net earnings	380,112	377,648
Earnings attributable to noncontrolling interests	25,933	20,749
Net earnings attributable to Nucor stockholders	$ 354,179	$ 356,899
Net earnings per share:
Basic	$ 1.11	$ 1.11
Diluted	$ 1.10	$ 1.11
Average shares outstanding:
Basic	319,421	320,224
Diluted	320,474	321,146
Dividends declared per share	$ 0.3800	$ 0.3775