Divestitures - Discontinued Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations (net of tax)	$ 0	$ 0	$ 202,131
Chemetall Surface Treatment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales			813,285
Cost of goods sold			416,934
Operating expenses, net			268,402
Interest and financing expenses			38,227
Other income, net			(2,485)
Gain on sale of discontinued operations			(387,980)
Income before income taxes			480,187
Income tax expense			278,056
Income from discontinued operations (net of tax)			202,131
Depreciation and amortization			35,194
Capital expenditures			$ 19,281