Industry Segment and Foreign Operations - Revenue by Geographic Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 1,970,129	$ 1,563,150	$ 1,804,436
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	762,269	601,118	670,082
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	183,485	133,743	159,259
All other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,024,375	828,289	975,095
Polymer
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,098,785	857,558	1,052,968
Polymer | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	422,599	311,129	352,735
Polymer | Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	125,146	89,304	107,661
Polymer | All other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	551,040	457,125	592,572
Chemical
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	871,344	705,592	751,468
Chemical | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	339,670	289,989	317,347
Chemical | Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	58,339	44,439	51,598
Chemical | All other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 473,335	$ 371,164	$ 382,523