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Loans - Impaired Loans - Average Recorded Investment and Interest Income Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Average Recorded Investment
With no related allowance recorded	$ 18,047	$ 20,982	$ 27,868
With an allowance recorded	3,153	605	518
Total impaired loans	21,200	21,587	28,386
Interest Income Recognized
With no related allowance recorded	45	323	303
With an allowance recorded	201		3
Total impaired loans	246	323	306
Commercial
Average Recorded Investment
With no related allowance recorded	120	155	785
With an allowance recorded		2	2
Lease financing receivables
Average Recorded Investment
With no related allowance recorded	272	183
Real estate - commercial | Owner occupied general purpose
Average Recorded Investment
With no related allowance recorded	1,168	2,098	4,720
Interest Income Recognized
With no related allowance recorded		87	82
Real estate - commercial | Owner occupied special purpose
Average Recorded Investment
With no related allowance recorded	364	574	1,280
Real estate - commercial | Non-owner occupied general purpose
Average Recorded Investment
With no related allowance recorded	1,453	1,395	2,939
With an allowance recorded	123	123	38
Interest Income Recognized
With no related allowance recorded		2	3
Real estate - commercial | Non-owner occupied special purpose
Average Recorded Investment
With no related allowance recorded	507	507	712
Real estate - commercial | Retail properties
Average Recorded Investment
With no related allowance recorded	1,130	589
Real estate - commercial | Farm
Average Recorded Investment
With no related allowance recorded		636	636
Real estate - residential | Investor
Average Recorded Investment
With no related allowance recorded	1,106	1,874	2,251
With an allowance recorded	414		67
Interest Income Recognized
With no related allowance recorded		47	51
With an allowance recorded	43
Real estate - residential | Multifamily
Average Recorded Investment
With no related allowance recorded	2,362
Real estate - residential | Owner occupied
Average Recorded Investment
With no related allowance recorded	7,516	10,181	10,979
With an allowance recorded	2,123	457	68
Interest Income Recognized
With no related allowance recorded	44	158	160
With an allowance recorded	123
Real estate - residential | Revolving and junior liens
Average Recorded Investment
With no related allowance recorded	1,804	2,608	2,484
With an allowance recorded	493	23	208
Interest Income Recognized
With no related allowance recorded	1	29	7
With an allowance recorded	35		3
Consumer
Average Recorded Investment
With no related allowance recorded	4
Construction Loans | Real estate - commercial | Homebuilder
Average Recorded Investment
With no related allowance recorded			895
Construction Loans | Real estate - commercial | Commercial speculative
Average Recorded Investment
With no related allowance recorded	37	79	42
Construction Loans | Real estate - commercial | All other
Average Recorded Investment
With no related allowance recorded	$ 204	$ 103	145
With an allowance recorded			$ 135

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
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+ References

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

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+ References

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

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