Short And Long-Term Debt (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Short And Long-Term Debt Instrument [Line Items]
Percentage of proceeds from certain asset sales required to pay down term loan		100.00%
Interest expense		$ 716,000	$ 553,000	$ 369,000
Debt		11,500,000
Interest Rate Swap [Member]
Short And Long-Term Debt Instrument [Line Items]
Other current liabilities		(8,000)	19,000
Quarterly installments		250,000
Interest rate swap, notional amount		$ 3,750,000
Federal Funds Rate [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments		0.50%
Domestic Term-Loan [Member]
Short And Long-Term Debt Instrument [Line Items]
Loan amount	$ 4,500,000	$ 6,500,000
Quarterly installments		250,000
Debt		$ 6,250,000	5,250,000
Note Payable [Member]
Short And Long-Term Debt Instrument [Line Items]
Debt			$ 2,000,000
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments		2.50%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Interest Rate Swap [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments		0.80%
Minimum [Member] | Federal Funds Rate [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments		(0.25%)
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments		4.00%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Interest Rate Swap [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments		1.45%
Maximum [Member] | Federal Funds Rate [Member]
Short And Long-Term Debt Instrument [Line Items]
Basis spread on variable rate of debt instruments		1.25%
Domestic Asset-based Revolving Credit Facility [Member]
Short And Long-Term Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity		$ 9,000,000
Inventory cap on borrowing base	4,000,000	4,500,000
Annual capital expenditure allowed	$ 4,500,000	$ 5,500,000
Credit facility, non-use fee percentage		0.25%
Weighted average interest rate of debt instruments		5.51%	4.36%	3.68%
Credit facility, outstanding balance		$ 4,000,000	$ 3,218,000
Credit facility, available borrowing capacity		5,000,000	5,121,000
Interest expense		80,000	57,000	$ 72,000
Debt		4,000,000	3,218,000
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
Debt
Foreign Overdraft And Letter Of Credit Facility [Member]
Short And Long-Term Debt Instrument [Line Items]
Weighted average interest rate of debt instruments		3.87%	3.50%	3.37%
Credit facility, outstanding balance		$ 1,250,000	$ 1,243,000
Credit facility, available borrowing capacity		545,000	455,000
Debt		$ 1,250,000	$ 1,243,000
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%