Income Taxes - Components of Net Deferred Tax Liability (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Tax effect of temporary differences related to:
Inventories	$ 400	$ 300
Accrued OPEB costs	400	500
Accrued pension costs	1,700	1,800
Accrued employee benefits	1,100	1,200
Accrued environmental liabilities	33,600	24,600
Other accrued liabilities and deductible differences	300	400
Tax Loss & Credit Carryforwards	1,200
Adjusted gross deferred tax assets (liabilities)	38,700	28,800
Netting of items by tax jurisdiction	(38,700)	(28,800)
Marketable securities	(5,600)	(18,400)
Property and equipment	(2,600)	(2,700)
Goodwill	(1,700)	(1,700)
Other taxable differences	(2,400)	(3,000)
Investment in Kronos Worldwide, Inc.	(57,800)	(52,300)
Adjusted gross deferred tax assets (liabilities)	(70,100)	(78,100)
Netting of items by tax jurisdiction	38,700	28,800
Net noncurrent deferred tax asset (liability)	$ (31,373)	$ (49,315)