Acquisitions (Narratives) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Financing used to fund purchase price from existing credit facility	$ 375,000,000				$ 500,000,000				$ 375,000,000	$ 500,000,000
Net income from continuing operations	6,475,000	$ (16,976,000)	$ 14,332,000	$ (20,663,000)	990,000	$ 15,052,000	$ 19,871,000	$ 22,548,000	(16,833,000)	58,461,000	$ 61,564,000
Sales	192,524,000	$ 184,370,000	$ 186,260,000	192,136,000	198,313,000	$ 205,968,000	$ 214,095,000	$ 207,948,000	755,290,000	826,324,000	851,834,000
Proceeds from Previous Acquisition				$ 0						0	4,250,000
Goodwill	67,708,000				81,404,000				67,708,000	81,404,000	81,404,000
Payments to Acquire Property, Plant, and Equipment									23,355,000	50,864,000	$ 40,814,000
Futura Industries [Member]
Business Acquisition [Line Items]
Business Combinations Accretion to Diluted Earnings Per Share	0.03								0.12
Other Assets and Deferred Charges [Member] | kaleo [Member]
Business Acquisition [Line Items]
Investment Owned, at Fair Value	$ 34,600,000				$ 95,500,000				$ 34,600,000	$ 95,500,000