Fair Value Disclosure (Schedule of Assets and Liabilities) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Quoted prices in active markets for identical assets (level 1)
Assets:
Available for sale securities	$ 9,166	$ 7,882
Interest rate swap agreements	0
Assets	9,166	7,882
Liabilities:
Interest rate swap agreements		0
Liabilities		0
Significant other observable inputs (level 2)
Assets:
Available for sale securities	0	0
Interest rate swap agreements	42
Assets	42	0
Liabilities:
Interest rate swap agreements		339
Liabilities		339
Significant unobservable inputs (level 3)
Assets:
Available for sale securities	0	0
Interest rate swap agreements	0
Assets	0	0
Liabilities:
Interest rate swap agreements		0
Liabilities		0
Estimate of Fair Value Measurement
Assets:
Available for sale securities	9,166	7,882
Interest rate swap agreements	42
Assets	$ 9,208	7,882
Liabilities:
Interest rate swap agreements		339
Liabilities		$ 339

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
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Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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Fair value of financial and nonfinancial obligations.

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