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Derivative Financial Instruments (Narrative) (Details) $ in Thousands	1 Months Ended		6 Months Ended
	Mar. 31, 2016 USD ($) contract	Jul. 31, 2009 USD ($) contract	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Derivative [Line Items]
Gain on derivative			$ 755
Increase in fair value of derivatives			755
Deferred tax asset on gain on derivative			$ 204
Cash flow hedge ineffectiveness			0
Interest Rate Swap [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 30,000	$ 20,000
Number of interest rate swap contracts | contract	4	3
Interest rate swap fair value			$ 1,500	$ 800
Swap Contract - 3-Year $5 million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 5,000
Derivative, maturity date	Jun. 17, 2019
Swap Contract - 5-Year $5 million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 5,000
Derivative, maturity date	Mar. 17, 2021
Swap Contract - 10-Year $15 million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 15,000
Derivative, maturity date	Mar. 17, 2026
Swap Contract- 7 year $5 Million [Member]
Derivative [Line Items]
Interest rate swap notional amount	$ 5,000
Derivative, maturity date	Mar. 17, 2023

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- Definition

Information on the swap contracts and the number of swaps

+ References

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

A disclosure of an assertion that the amount of cash flow hedge ineffectiveness is immaterial.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)(1)
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from derivative instruments.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 25
-Paragraph 20
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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

+ References

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-SubTopic 20
-Section 55
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Amount of increase in the fair value of derivatives recognized in the income statement.

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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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Date the derivative contract matures, in CCYY-MM-DD format.

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