Acquisitions - Other Acquisitions (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 22,270	$ 0
Net sales	221,290	$ 217,100
Plastic Srl [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	22,300
Net sales			$ 12,000
Non-cash purchase accounting related expenses	1,000
Selling, General and Administrative Expenses [Member] | Plastic Srl [Member]
Business Acquisition [Line Items]
Non-cash purchase accounting related expenses	900
Cost of Sales [Member] | Plastic Srl [Member]
Business Acquisition [Line Items]
Non-cash purchase accounting related expenses	$ 100