Investments in debt and equity securities which are categorized neither as held-to-maturity nor trading and which are intended to be sold or mature more than one year from the balance sheet date or operating cycle, if longer. Such securities are reported at fair value; unrealized gains (losses) related to Available-for-sale Securities are excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain (loss) of an Available-for-sale security that is designated as being hedged in a fair value hedge is recognized in earnings during the period of the hedge, as are other than temporary declines in fair value below the cost basis for investments in equity securities and debt securities that an entity intends to sell or it is more likely than not that it will be required to sell before the recovery of its amortized cost basis. Other than temporary declines in fair value below the cost basis for debt securities categorized as Available-for-sale that an entity does not intend to sell and for which it is not more likely than not that the entity will be required to sell before the recovery of its amortized cost basis are bifurcated into credit losses and losses related to all other factors. Other than temporary declines in fair value below cost basis related to credit losses are recognized in earnings, and losses related to all other factors are recognized in other comprehensive income.

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Aggregate impact of foreign currency derivatives on earnings for the period. Includes impact of foreign currency cash flow hedge ineffectiveness and the ineffectiveness of fair value hedging derivatives and full change in fair value of the foreign currency derivatives not designated as hedging instruments.

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Fair Value Measurements and Financial Instruments - Additional Information (Detail)							3 Months Ended
	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 Kronos Worldwide, Inc. 2014 Term Loan Per Thousand Dollar Principal Amount USD ($)	Dec. 31, 2014 Kronos Worldwide, Inc. 2014 Term Loan Per Thousand Dollar Principal Amount USD ($)	Mar. 31, 2015 Amalgamated Sugar Company LLC USD ($)	Dec. 31, 2014 Amalgamated Sugar Company LLC USD ($)	Mar. 31, 2015 Chemicals Forward Contracts USD ($)	Mar. 31, 2015 Chemicals Norwegian Kroner Forward Contracts USD ($)	Mar. 31, 2015 Chemicals Norwegian Kroner Forward Contracts Euro EUR (€)	Mar. 31, 2015 Minimum Chemicals Norwegian Kroner Forward Contracts USD ($)	Mar. 31, 2015 Minimum Chemicals Norwegian Kroner Forward Contracts NOK	Mar. 31, 2015 Minimum Chemicals Norwegian Kroner Forward Contracts Euro NOK	Mar. 31, 2015 Maximum Chemicals Norwegian Kroner Forward Contracts USD ($)	Mar. 31, 2015 Maximum Chemicals Norwegian Kroner Forward Contracts NOK	Mar. 31, 2015 Maximum Chemicals Norwegian Kroner Forward Contracts Euro NOK
Financial Instrument At Fair Value [Line Items]
Notional amount currency forward contract								$ 16,200,000	€ 15,000,000
Exchange floor rate											6.75	8.53		7.11	8.56
Maturity rate of derivative									5,000,000	2,700,000			5,000,000
Estimated fair value of currency forward contracts	(4,500,000)	(4,200,000)					(4,500,000)
Currency transaction loss							(4,500,000)
Estimated market price of the notes			1,012.50	983.1
Principal amount of debt instrument			1,000	1,000
Marketable securities	$ 255,600,000	$ 255,600,000			$ 250,000,000	$ 250,000,000