Acquisition - Additional Information (Details)		3 Months Ended								12 Months Ended
	Oct. 01, 2018 USD ($) Employee t	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 150,816,000				$ 153,463,000				$ 150,816,000	$ 153,463,000
Intangible assets, net		83,735,000				93,614,000				83,735,000	93,614,000
Net sales		230,972,000	$ 232,515,000	$ 235,053,000	$ 229,133,000	$ 229,480,000	$ 209,855,000	$ 215,742,000	$ 211,209,000	927,673,000	866,286,000	$ 800,362,000
Operating income										54,635,000	21,942,000	33,252,000
Selling, general and administrative expenses										94,967,000	111,721,000	$ 110,534,000
G P Business [Member]
Business Acquisition [Line Items]
Business acquisition purchase price	$ 188,000,000
Business acquisition, date of completion	Oct. 01, 2018
Annual production capacity | t	32,000
Number of employees at manufacturing facility | Employee	220
Goodwill		74,770,000								74,770,000
Intangible assets, net		43,600,000								43,600,000
Goodwill deductible for tax purposes		$ 0								$ 0
Acquired intangible assets estimated remaining life										13 years
Net sales											23,100,000
Operating income											2,400,000
Selling, general and administrative expenses											$ 5,100,000
G P Business [Member] | Minimum [Member]
Business Acquisition [Line Items]
Acquired property, plant and equipment, estimated remaining lives										5 years
G P Business [Member] | Maximum [Member]
Business Acquisition [Line Items]
Acquired property, plant and equipment, estimated remaining lives										25 years