Short And Long-Term Debt (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Short And Long-Term Debt Instrument [Line Items]
Interest expense	$ 188,000	$ 182,000
Domestic Term-Loan [Member]
Short And Long-Term Debt Instrument [Line Items]
Loan amount	6,500,000
Quarterly installments	$ 250,000
Percentage of proceeds from certain asset sales required to pay down term loan	100.00%
Domestic Asset-based Revolving Credit Facility [Member]
Short And Long-Term Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 9,000,000
Weighted average interest rate of debt instruments	5.26%		5.51%
Credit facility, available borrowing capacity	$ 3,135,000		$ 5,000,000
Letters Of Credit [Member]
Short And Long-Term Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	200,000
Capital Expenditure Loan Facility [Member]
Short And Long-Term Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 2,500,000
Foreign Overdraft And Letter Of Credit Facility [Member]
Short And Long-Term Debt Instrument [Line Items]
Weighted average interest rate of debt instruments	4.26%		3.87%
Credit facility, available borrowing capacity	$ 571,000		$ 545,000
Foreign Overdraft And Letter Of Credit Facility [Member] | Minimum [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments	0.75%
Foreign Overdraft And Letter Of Credit Facility [Member] | Maximum [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments	2.50%