Business Acquisitions - Narratives (Details) - USD ($) $ in Thousands			3 Months Ended								12 Months Ended
	May 15, 2017	Mar. 11, 2016	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition
Goodwill			$ 71,057				$ 61,744				$ 71,057	$ 61,744	$ 33,865
Cost of goods sold											282,562	256,251	255,201
Net Income (Loss) Attributable to Parent			$ (13,621)	$ 9,619	$ 9,966	$ 8,484	$ 8,310	$ 3,720	$ 14,487	$ 7,863	$ 14,448	$ 34,380	$ 6,954
CTG Advanced Materials, LLC [Member]
Business Acquisition
Acquired Finite-lived Intangible Asset, Residual Value		$ 35,427
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		73,731
Business Acquisition, Goodwill, Expected Tax Deductible Amount		27,879
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets		4,215
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		6,173
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets		37
Goodwill		27,879
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		(668)
Finite-lived Intangible Assets Acquired		$ 35,427
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		14 years 9 months 20 days
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		$ 4
Business Acquisition, Transaction Costs		804
Noliac A/S [Member]
Business Acquisition
Acquired Finite-lived Intangible Asset, Residual Value	$ 9,142
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	22,266
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	2,836
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	580
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	395
Goodwill	9,313
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(3,145)
Finite-lived Intangible Assets Acquired	$ 9,142
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	13 years 8 months
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	$ 0
Business Acquisition, Transaction Costs		0
Developed Technology | CTG Advanced Materials, LLC [Member]
Business Acquisition
Finite-lived Intangible Assets Acquired		$ 23,730
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		15 years
Developed Technology | Noliac A/S [Member]
Business Acquisition
Finite-lived Intangible Assets Acquired	$ 7,581
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	15 years
Customer Relationships and Contracts | CTG Advanced Materials, LLC [Member]
Business Acquisition
Finite-lived Intangible Assets Acquired		$ 11,502
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		14 years 7 months 6 days
Customer Relationships and Contracts | Noliac A/S [Member]
Business Acquisition
Finite-lived Intangible Assets Acquired	$ 937
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Technology and other intangibles | CTG Advanced Materials, LLC [Member]
Business Acquisition
Finite-lived Intangible Assets Acquired		$ 195
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		9 months 18 days
Technology and other intangibles | Noliac A/S [Member]
Business Acquisition
Finite-lived Intangible Assets Acquired	$ 624
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	3 years