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Loans and Allowance for Loan Losses - Troubled Debt Restructuring by Class (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans removed from TDR designation | loan	0	0
Recorded investment in Troubled Debt Restructurings	$ 16,384,000	$ 18,168,000
Accruing TDR loans	0	0
Commercial loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	2,050,000	2,207,000
Commercial real estate loans | Commercial real estate, owner-occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	6,999,000	6,993,000
Commercial real estate loans | Commercial real estate, investor
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	2,193,000	2,256,000
Commercial real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	2,969,000	3,245,000
Residential loans | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	348,000	625,000
Residential loans | Other residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	1,159,000	1,965,000
Consumer loans | Installment and other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	$ 666,000	$ 877,000

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Financing Receivable, Modifications, Removal From Troubled Debt Restructuring, Number Of Contracts

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The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18845-111554

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