Income Taxes - Component of Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Expected tax expense (benefit), at U.S. federal statutory income tax rate of 35%	$ 600	$ (17,300)	$ (500)	$ (14,200)
Rate differences on equity in earnings (losses) of Kronos	(100)	(3,200)	200	(4,700)
Adjustment to the reserve for uncertain tax positions, net				(3,000)
Nontaxable income		(100)	(200)	(200)
U.S. state income taxes and other, net	(200)			100
Income tax expense (benefit)	$ 330	$ (20,507)	$ (492)	$ (21,953)