Accrued Liabilities (Narrative) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities [Abstract]
Accrued product liability	$ 5,055,000	$ 4,949,000
Accrued payroll liability	6,341,000	5,130,000
Environmental accrued liability	1,050,000	1,120,000
Other accrued liabilities	$ 878,000	$ 812,000