Long-Term Debt (Narrative) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Amount outstanding under revolving credit facility	$ 85,298,000	$ 60,082,000
2019	119,000
2020	94,000
2021	85,064,000
2022	21,000
Thereafter	0
Amended and Restated Revolving Credit Agreement \| Bank revolving credit facility \| Unsecured Debt
Debt Instrument [Line Items]
Aggregate commitments	250,000,000
Maximum amount of aggregate commitments	50,000,000
Amount outstanding under revolving credit facility	85,000,000	$ 60,000,000
Available borrowings	163,612,000
Amended and Restated Revolving Credit Agreement \| Standby Letters of Credit \| Unsecured Debt
Debt Instrument [Line Items]
Amount of capacity	$ 1,388,000

Line of Credit Facility, Accordion Feature, Increase Limit

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- Definition

Long-term Debt, Maturities, Repayments of Principal after Year Four

+ References

No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for financing purchases of goods acquired for inventory or imminent delivery to a customer.

+ References

No definition available.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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- Definition

Amount of long-term debt and capital lease obligations including current maturities.

+ References

No definition available.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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