Loans and Allowance (Impaired Loans) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Impaired Financing Receivable With Related Allowance [Abstract]
Specific Allowance	$ 100	$ 100	$ 100
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	3,607	3,757	6,700
Unpaid principal balance, total	3,677	3,757	6,700
Average investment in impaired loans, total	3,408	5,222	7,578
Interest income recognized, total	40	109	225
Commercial Real Estate [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	878	665	3,608
Unpaid principal balance	878	665	3,608
Average investment in impaired loans	765	2,207	4,115
Interest income recognized	1	68	172
Impaired Financing Receivable With Related Allowance [Abstract]
Recorded balance	214	214	676
Unpaid principal balance	214	214	676
Specific Allowance	100	100	100
Average investment in impaired loans	214	416	793
Interest income recognized			20
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	1,092	879	4,284
Unpaid principal balance, total	1,092	879	4,284
Average investment in impaired loans, total	979	2,623	4,908
Interest income recognized, total	1	68	192
Commercial Segment [Member] \| Construction Loans [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	700	822	595
Unpaid principal balance	700	822	595
Average investment in impaired loans	762	874	735
Interest income recognized	33	40	31
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	700	822	595
Unpaid principal balance, total	700	822	595
Average investment in impaired loans, total	762	874	735
Interest income recognized, total	33	40	31
Commercial Segment [Member] \| Commercial and Industrial [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	272	187	214
Unpaid principal balance	342	187	214
Average investment in impaired loans	216	204	423
Interest income recognized	5	1	2
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	272	187	214
Unpaid principal balance, total	342	187	214
Average investment in impaired loans, total	216	204	423
Interest income recognized, total	5	1	2
Consumer [Member] \| First Mortgage [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	1,543	1,869	1,126
Unpaid principal balance	1,543	1,869	1,126
Average investment in impaired loans	1,451	1,328	1,131
Interest income recognized	1
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	1,543	1,869	1,126
Unpaid principal balance, total	1,543	1,869	1,126
Average investment in impaired loans, total	1,451	1,328	1,131
Interest income recognized, total	$ 1
Consumer [Member] \| Second Mortgage [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance			481
Unpaid principal balance			481
Average investment in impaired loans		193	381
Impaired Financing Receivables Total [Abstract]
Recorded balance, total			481
Unpaid principal balance, total			481
Average investment in impaired loans, total		$ 193	$ 381

Impaired Financing Receivable With No Related Allowance [Abstract].

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

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