Basis of Interim Presentation - Schedule of Adjustments to Condensed Consolidated Statement of Earnings (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold	$ 4,591,153	$ 3,608,000	$ 13,111,226	$ 10,669,103
Provision for income taxes	104,500	152,807	442,239	318,388
Net earnings	266,105	331,365	985,477	725,231
Earnings attributable to noncontrolling interests	11,255	25,918	50,680	88,599
Net earnings attributable to Nucor stockholders	254,850	305,447	934,797	636,632
Net earnings per share:
Cost of products sold	4,591,153	3,608,000	13,111,226	10,669,103
Provision for income taxes	104,500	152,807	442,239	318,388
Net earnings	266,105	331,365	985,477	725,231
Earnings attributable to noncontrolling interests	11,255	25,918	50,680	88,599
Net earnings attributable to Nucor stockholders	$ 254,850	$ 305,447	$ 934,797	$ 636,632
Basic	$ 0.79	$ 0.95	$ 2.91	$ 1.99
Diluted	$ 0.79	$ 0.95	$ 2.90	$ 1.99
As Originally Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold		$ 3,665,900		$ 10,774,040
Provision for income taxes		131,788		281,401
Net earnings		294,484		657,281
Earnings attributable to noncontrolling interests		24,448		82,719
Net earnings attributable to Nucor stockholders		270,036		574,562
Net earnings per share:
Cost of products sold		3,665,900		10,774,040
Provision for income taxes		131,788		281,401
Net earnings		294,484		657,281
Earnings attributable to noncontrolling interests		24,448		82,719
Net earnings attributable to Nucor stockholders		$ 270,036		$ 574,562
Basic		$ 0.84		$ 1.79
Diluted		$ 0.84		$ 1.79
Effect of Change [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold		$ (57,900)		$ (104,937)
Provision for income taxes		21,019		36,987
Net earnings		36,881		67,950
Earnings attributable to noncontrolling interests		1,470		5,880
Net earnings attributable to Nucor stockholders		35,411		62,070
Net earnings per share:
Cost of products sold		(57,900)		(104,937)
Provision for income taxes		21,019		36,987
Net earnings		36,881		67,950
Earnings attributable to noncontrolling interests		1,470		5,880
Net earnings attributable to Nucor stockholders		$ 35,411		$ 62,070
Basic		$ 0.11		$ 0.20
Diluted		$ 0.11		$ 0.20