Accrued Liabilities (Details) - Accrued liabilities - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities (Details) - Accrued liabilities [Line Items]
Taxes payable	$ 1,149,000	$ 1,114,000
Current portion of pension liability (see Note 15 – Pension Plan)	1,008,000	641,000
Interest payable	933,000	875,000
Warranty reserve	438,000	430,000
Deferred revenues	271,000	787,000
Audit fees	134,000	122,000
Compensation and employee benefits	90,000	336,000
Directors fees		1,202,000
Other	532,000	539,000
Accrued Liabilities, Total	$ 4,555,000	$ 6,046,000