Income Taxes Reconciliation of Total Gross Liability Related to Uncertain Tax Positions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 25,384	$ 95,715	$ 24,969
Acquisition of Rockwood	0	0	124,758
Divestitures	0	(55,881)	0
Additions for tax positions related to prior years	0	548	4,329
Reductions for tax positions related to prior years	(1,933)	(1,253)	(46,211)
Additions for tax positions related to current year	1,132	1,271	202
Lapses in statutes of limitations/settlements	(4,198)	(12,591)	(6,736)
Foreign currency translation adjustment	1,053	(2,425)	(5,596)
Ending Balance	$ 21,438	$ 25,384	$ 95,715