Marketable Securities - Schedule of Marketable Securities (Detail) (Level 1 [Member], Valhi common stock [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Level 1 [Member] \| Valhi common stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Market value	$ 197,485	$ 179,662
Cost basis	24,347	24,347
Unrealized gains	$ 173,138	$ 155,315

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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