Investment in Kronos Worldwide, Inc. - Changes in Carrying Value of Investment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Balance at the beginning of the period			$ 292,206
Equity in loss of Kronos	$ (2,516)	$ 13,991	(7,153)	$ 31,524
Dividends received from Kronos			(13,384)	$ (13,384)
Equity in Kronos' other comprehensive income (loss):
Balance at the end of the period	268,469		268,469
Kronos
Balance at the beginning of the period			292,200
Equity in loss of Kronos			(7,100)
Dividends received from Kronos			(13,400)
Equity in Kronos' other comprehensive income (loss):
Currency translation			(3,800)
Defined benefit pension plans			500
Other			100
Balance at the end of the period	$ 268,500		$ 268,500