Accrued Liabilities (Details) - Accrued liabilities - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities (Details) - Accrued liabilities [Line Items]
Directors fees	$ 1,202,000	$ 1,148,000
Taxes payable	1,114,000	1,083,000
Interest payable	875,000	731,000
Deferred revenues	787,000	1,000,000
Current portion of pension liability (see Note 15 – Pension Plan)	641,000	623,000
Warranty reserve	430,000	405,000
Compensation and employee benefits	336,000	636,000
Audit fees	122,000	148,000
Other	539,000	558,000
Accrued Liabilities, Total	$ 6,046,000	$ 6,332,000