Income Taxes - Component of Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Expected tax expense, at U.S. federal statutory income tax rate of 21%	$ 12,800	$ 2,900	$ 6,000
Non-taxable dividends received from Kronos	(5,300)	(5,300)	(5,300)
U.S. state income taxes and other, net		(100)	(100)
Income tax expense (benefit)	$ 7,479	$ (2,515)	$ 579