Stockholders' Equity (Schedule Of Changes In Stockholders' Equity) (Parenthetical) (Detail)	Jun. 30, 2012
Nucor-Yamato Steel Company [Member]
Stockholders' Equity [Line Items]
Noncontrolling interest, ownership percentage by parent	51.00%
Barker Steel Company, Inc. [Member]
Stockholders' Equity [Line Items]
Noncontrolling interest, ownership percentage by parent	90.00%

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