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Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Commercial lines of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitments and standby letters of credit, off-balance sheet	$ 216,774	$ 191,305
Revolving home equity lines
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitments and standby letters of credit, off-balance sheet	148,143	130,359
Undisbursed construction loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitments and standby letters of credit, off-balance sheet	44,798	39,442
Personal and other lines of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitments and standby letters of credit, off-balance sheet	10,635	11,112
Standby letters of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitments and standby letters of credit, off-balance sheet	1,939	4,381
Lines of credit and standby letters of credit, unused
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitments and standby letters of credit, off-balance sheet	$ 422,289	376,599
Percentage of commitments expiring in 2017	42.00%
Percentage of commitments expiring between 2018 and 2024	42.00%
Percentage of commitments expiring 2025 and thereafter	16.00%
Lines of credit and standby letters of credit, unused | Interest Payable and Other Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Allowance for off-balance sheet commitments	$ 899	$ 749

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- Definition

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Loan Commitments And Standby Letters Of Credit, Percentage Expiring, After Year Eight

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Loan Commitments and Standby Letters of Credit, Percentage Expiring in Next Twelve Months

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Loan Commitments And Standby Letters of Credit, Percentage Expiring In Year Two Through Eight

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Off-balance Sheet Arrangements, Liabilities, Current Exposure

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