Business Combinations - Estimated Fair Value of Intangible Assets Acquired (Details) - USD ($) $ in Thousands		12 Months Ended
Apr. 23, 2018	Dec. 31, 2018
Certified Thermoplastics Co., LLC
Business Acquisition [Line Items]
Intangible assets	$ 8,100
Customer relationships
Business Acquisition [Line Items]
Useful Life (In years)		17 years
Customer relationships \| Certified Thermoplastics Co., LLC
Business Acquisition [Line Items]
Useful Life (In years)	10 years
Intangible assets	$ 6,900
Trade names and trademarks \| Certified Thermoplastics Co., LLC
Business Acquisition [Line Items]
Useful Life (In years)	10 years
Intangible assets	$ 1,200

The amount of identifiable intangible assets recognized as of the acquisition date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 55
-Paragraph 37
-URI http://asc.fasb.org/extlink&oid=108330185&loc=d3e2207-128464

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant