Income Taxes - Component of Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Expected tax expense (benefit), at U.S. federal statutory income tax rate of 35%	$ (1,100)	$ 3,100
Rate differences on equity in earnings (losses) of Kronos	300	(1,500)
Adjustment to the reserve for uncertain tax positions, net		(3,000)
Nontaxable income	(200)	(100)
U.S. state income taxes and other, net	200	100
Income tax benefit	$ (822)	$ (1,446)