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