Income Taxes - Component of Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Expected tax expense (benefit), at U.S. federal statutory income tax rate of 35%	$ 4,900	$ (18,000)	$ 12,100
Rate differences on equity in earnings (losses) of Kronos	(7,400)	(7,400)	(7,400)
Adjustment to the reserve for uncertain tax positions, net		(3,000)
U.S. state income taxes and other, net	(300)	(200)	300
Income tax expense (benefit)	$ (2,777)	$ (28,611)	$ 5,003