Income Taxes - Components of Net Deferred Tax Liability (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Tax effect of temporary differences related to:
Inventories	$ 500	$ 800
Accrued OPEB costs	1,100	1,400
Accrued pension costs	4,600	4,400
Accrued employee benefits	2,000	1,900
Accrued environmental liabilities	39,900	38,800
Other accrued liabilities and deductible differences	400	800
Tax loss and tax credit carryforwards	500	2,200
Adjusted gross deferred tax assets (liabilities)	49,000	50,300
Netting of items by tax jurisdiction	(49,000)	(50,300)
Marketable securities	(6,400)	(31,900)
Property and equipment	(4,500)	(4,600)
Goodwill	(2,600)	(2,600)
Other taxable differences	(4,300)	(4,200)
Investment in Kronos Worldwide, Inc.	(56,200)	(90,100)
Adjusted gross deferred tax assets (liabilities)	(74,000)	(133,400)
Netting of items by tax jurisdiction	49,000	50,300
Net noncurrent deferred tax asset (liability)	$ (25,035)	$ (83,158)