Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 186,716	$ 171,164
Property and equipment, net	28,543	28,950
Other noncurrent assets	5,259	5,262
Total assets	573,043	548,150
Current liabilities	30,128	27,507
Accrued pension costs	4,788	6,392
Other	2,124	3,780
Stockholders' equity	342,895	311,877
Total liabilities and equity	573,043	548,150
Kronos
Schedule Of Equity Method Investments [Line Items]
Current assets	1,219,100	1,218,300
Property and equipment, net	503,000	524,600
Investment in TiO2 joint venture	105,500	103,300
Other noncurrent assets	176,900	190,500
Total assets	2,004,500	2,036,700
Current liabilities	259,700	260,200
Long-term debt	461,100	486,700
Accrued pension costs	349,300	372,600
Other	112,400	120,700
Stockholders' equity	822,000	796,500
Total liabilities and equity	$ 2,004,500	$ 2,036,700