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Derivative Financial Instruments and Hedging Activities - Information on Derivatives (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) derivative	Dec. 31, 2017 USD ($)
Fair value hedges:
Interest rate contracts fair value, Asset derivatives	$ 161	$ 74
Interest rate contracts fair value, Liability derivatives	375	740
Carrying Amounts of Hedged Assets	17,917	19,260
Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Loans	6	431
Interest and fees on loans	79,527	66,799
Fair value hedge
Fair value hedges:
Net hedge ineffectiveness gain (loss), derivatives	13	31
Fair value hedge | Interest income
Fair value hedges:
Increase in value of designated interest rate swaps due to LIBOR interest rate movements	452	212
Payment on interest rate swaps	(149)	(333)
Decrease in value of hedged loans	(425)	(166)
Decrease in value of yield maintenance agreement	(14)	(15)
Net loss on derivatives recognized against interest income	(136)	(302)
Fair value hedge | Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivatives, accrued interest, interest rate swaps	$ 3	8
Interest rate swap | Fair value hedge | Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Number of derivative instruments | derivative	5
Interest rate swap | Fair value hedge | Designated as hedging instrument | Other assets
Fair value hedges:
Interest rate contracts notional amounts, Asset derivatives	$ 8,895	4,019
Interest rate swap | Fair value hedge | Designated as hedging instrument | Other liabilities
Fair value hedges:
Interest rate contracts notional amount, Liability derivatives	9,016	14,810
Interest rate contract | Fair value hedge | Designated as hedging instrument | Other assets
Fair value hedges:
Interest rate contracts fair value, Asset derivatives	161	74
Interest rate contract | Fair value hedge | Designated as hedging instrument | Other liabilities
Fair value hedges:
Interest rate contracts fair value, Liability derivatives	$ 375	$ 740

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