Nature of Operations and Basis of Presentation - Additional Information (Detail)	Dec. 31, 2018
Nucor-Yamato Steel Company [Member]
Summary Of Organization And Operations [Line Items]
Noncontrolling interest, ownership percentage by parent	51.00%

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant