Income Taxes - Components of Net Deferred Tax Liability (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Tax effect of temporary differences related to:
Inventories	$ 400	$ 400
Accrued OPEB costs	300	400
Accrued pension costs	700	1,700
Accrued employee benefits	1,200	1,100
Accrued environmental liabilities	31,700	33,600
Other accrued liabilities and deductible differences	200	300
Tax loss and credit carryforwards		1,200
Adjusted gross deferred tax assets (liabilities)	34,500	38,700
Netting of items by tax jurisdiction	(34,500)	(38,700)
Marketable securities	(5,400)	(5,600)
Property and equipment	(2,800)	(2,600)
Goodwill	(1,700)	(1,700)
Other taxable differences	(2,300)	(2,400)
Investment in Kronos Worldwide, Inc.	(56,300)	(57,800)
Adjusted gross deferred tax assets (liabilities)	(68,500)	(70,100)
Netting of items by tax jurisdiction	34,500	38,700
Net noncurrent deferred tax asset (liability)	$ (33,957)	$ (31,373)