Divestitures - Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations (net of tax)	$ 559,974	$ 23,185	$ (398,340)	$ 17,312	$ 0	$ 202,131	$ 32,476
Chemetall Surface Treatment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales						813,285	824,906
Cost of goods sold						416,934	488,267
Operating expenses, net						268,402	239,316
Interest and financing expenses						38,227	51,072
Other income, net						(2,485)	(4,214)
Gain on sale of discontinued operations						(387,980)	0
Income before income taxes						480,187	50,465
Income tax expense						278,056	17,989
Income from discontinued operations (net of tax)						202,131	32,476
Depreciation and amortization						35,194	78,903
Capital expenditures						$ 19,281	$ 23,738