Noncontrolling Interest in Subsidiaries - Noncontrolling Interest in Subsidiaries (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	$ 271.1	$ 336.3
Kronos Worldwide, Inc.
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	156.9	211.0
NL
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	41.8	54.4
CompX
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	15.2	14.4
BMI
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	32.2	31.7
LandWell
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	$ 25.0	$ 24.8

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.31)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 27

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 20

-Article 7

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant