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Marketable Securities - Additional Information (Detail) (Valhi common stock [Member], USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Valhi common stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Outstanding common stock, shares	14.4	14.4
Common stock quoted market price per share	$ 16.05	$ 12.50

X

- Definition

Outstanding common stock quoted market price per share.

+ References

No definition available.

+ Details

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X

- Definition

Balance held at close of period in number of shares.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 14

-Paragraph Column B

-Article 12



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 6

-Subparagraph (SX 210.12-14.Column B)

-URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611322-123010

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