Long-Term Debt - Long-Term Debt (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Long-term debt
Total debt	$ 938.1	$ 934.1
Less current maturities	9.2	9.3
Total long-term debt	928.9	924.8
VALHI, INC.
Long-term debt
Total debt	479.2	473.7
VALHI, INC. \| Notes Payable, Other Payables \| Snake River
Long-term debt
Total debt	250.0	250.0
VALHI, INC. \| Credit Facility \| Contran
Long-term debt
Total debt	229.2	223.7
Kronos Worldwide, Inc. \| 2014 Term Loan
Long-term debt
Total debt	345.1	345.9
WCS
Long-term debt
Financing capital lease	66.8	67.1
Tremont \| Promissory Note
Long-term debt
Total debt	17.3	17.4
BMI \| Bank note payable
Long-term debt
Total debt	10.1	10.3
LandWell \| Unsecured Debt
Long-term debt
Total debt	3.1	3.1
Other Subsidiary \| Other
Long-term debt
Total debt	16.5	16.6
Subsidiary
Long-term debt
Total debt	$ 458.9	$ 460.4

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

+ References

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 210.5-02.22)

-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 22

-Article 5

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section H

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

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