Income Taxes - Components of Net Deferred Tax Liability (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Tax effect of temporary differences related to:
Inventories	$ 300	$ 500
Accrued OPEB costs	500	1,000
Accrued pension costs	1,800	4,200
Accrued employee benefits	1,200	1,900
Accrued environmental liabilities	24,600	41,100
Other accrued liabilities and deductible differences	400	200
Adjusted gross deferred tax assets (liabilities)	28,800	48,900
Netting of items by tax jurisdiction	(28,800)	(48,900)
Marketable securities	(18,400)	(17,000)
Property and equipment	(2,700)	(4,400)
Goodwill	(1,700)	(2,600)
Other taxable differences	(3,000)	(3,300)
Investment in Kronos Worldwide, Inc.	(52,300)	(49,000)
Adjusted gross deferred tax assets (liabilities)	(78,100)	(76,300)
Netting of items by tax jurisdiction	28,800	48,900
Net noncurrent deferred tax asset (liability)	$ (49,315)	$ (27,445)