Short-Term Borrowings (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Short-Term Borrowings (Textual)
Purchases of federal funds	$ 38,000	$ 23,000
Retail repurchase agreements total amount	15,100
Repurchase agreements securities	15,082	10,532
Mortgage-backed securities	14,800	9,500
Retail Repurchase Agreements [Member]
Short-Term Borrowings (Textual)
Maximum amount of outstanding agreements at any month-end	18,400	20,600
Monthly average of such agreements totaled	$ 12,400	15,000
Short-term borrowings mature	within one month.
Repurchase agreements securities	$ 4,300	$ 5,100
Mortgage-backed securities maturity, basis of allocation description	This collateral has maturities from 2018 through 2042.

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Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

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Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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This item represents disclosure of the basis (methodology and assumptions) for allocating securities which do not have a single contractual maturity date, such as mortgage-backed securities, over several maturity groupings. Such securities are categorized as held-to-maturity.

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Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as held-to-maturity.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

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