Loans - Average Impaired Loans and Interest Income (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	$ 60,663	$ 45,911	$ 50,976
Interest Income Recognized	2,173	2,161	1,919
Commercial
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	23,098	16,915	21,641
Interest Income Recognized	658	819	709
SBA
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	7,770	11,574	14,594
Interest Income Recognized	221	407	586
Construction
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	5,500	5,709	6,810
Interest Income Recognized	184	290	37
Indirect automobile
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	2,616	2,117	1,829
Interest Income Recognized	264	234	284
Installment
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	473	422	473
Interest Income Recognized	194	120	128
Residential mortgage
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	18,657	7,970	4,789
Interest Income Recognized	548	174	112
Home equity lines of credit
Receivables with Imputed Interest [Line Items]
Average Recorded Investment	2,549	1,204	840
Interest Income Recognized	$ 104	$ 117	$ 63

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

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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