Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Line Items]
Foreign and export sales (as a percent)				53.10%	53.50%	54.20%
Export sales				$ 86,300	$ 56,800	$ 55,900
Sales to automotive market (as a percent)				42.90%	46.30%	48.30%
Cash received from trade receivables sold at time of sale (as a percent)	90.00%
Cash received from trade receivables sold when customer payment received (as a percent)	10.00%
Fees related to disposal of trade receivables	$ 100
Maximum amount subject to Receivables Purchases Agreements	10,000	$ 10,000		$ 10,000
Maximum aggregate amount subject to Receivables Purchases Agreements	50,000	50,000		$ 50,000
Finite-lived intangible asset useful life				11 years
Research and development expense				$ 11,200	$ 10,600	$ 10,800
Goodwill impairment		63,000		$ 63,000
Minimum
Accounting Policies [Line Items]
Finite-lived intangible asset useful life				2 years
Maximum
Accounting Policies [Line Items]
Finite-lived intangible asset useful life				17 years
Sales Revenue | Ford Motor Company | Customer Concentration Risk
Accounting Policies [Line Items]
Concentration risk (as a percent)				11.80%	14.80%	17.30%
Performance Materials
Accounting Policies [Line Items]
Goodwill impairment		63,000		$ 63,000
Trade Receivables
Accounting Policies [Line Items]
Disposal of assets	16,000	$ 16,000		$ 16,000
Proceeds from sale of trade receivables	$ 14,900
Forecast
Accounting Policies [Line Items]
Fees related to disposal of trade receivables			$ 1,000