Derivatives and Hedging Activities (Derivative Positions for Interest Rate Swaps which Qualify as Hedges) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Fair Value	$ 1,878,000		$ 1,878,000		$ 1,616,000
Amortization Of Deferred Hedge Gains Losses	61,000	$ 61,000	122,000	$ 122,000
Change in Fair Value on Loans Held for Sale	70,000	$ 153,000	44,000	$ 6,000
Notional amount of fair value hedged derivative	0		$ 0		0
Positions One [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount					$ 25,000,000
Receive (Variable) Index					3 Month LIBOR
Derivative, Variable Interest Rate					1.54%
Trade Date			Dec. 09, 2008
Derivative, Inception Date			Dec. 10, 2008
Maturity Date			Dec. 10, 2018
Pay Fixed Swap Rate					2.94%
Fair Value					$ (264,000)
Positions Two [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount					$ 25,000,000
Receive (Variable) Index					3 Month LIBOR
Derivative, Variable Interest Rate					1.59%
Trade Date			Apr. 01, 2016
Derivative, Inception Date			Jan. 17, 2017
Maturity Date			Dec. 15, 2021
Pay Fixed Swap Rate					1.36%
Fair Value					$ 772,000
Positions Three [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount					$ 25,000,000
Receive (Variable) Index					3 Month LIBOR
Derivative, Variable Interest Rate					1.59%
Trade Date			Apr. 01, 2016
Derivative, Inception Date			Jan. 17, 2017
Maturity Date			Dec. 15, 2021
Pay Fixed Swap Rate					1.36%
Fair Value					$ 763,000
Positions Four [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount					$ 25,000,000
Receive (Variable) Index					3 Month LIBOR
Derivative, Variable Interest Rate					1.42%
Trade Date			Jul. 18, 2017
Derivative, Inception Date			Aug. 15, 2017
Maturity Date			Aug. 15, 2022
Pay Fixed Swap Rate					1.88%
Fair Value					$ 345,000
Positions Five [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000		$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate	2.33%		2.33%
Trade Date			Dec. 09, 2008
Derivative, Inception Date			Dec. 10, 2008
Maturity Date			Dec. 10, 2018
Pay Fixed Swap Rate	2.94%		2.94%
Fair Value	$ (61,000)		$ (61,000)
Positions Six [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000		$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate	2.34%		2.34%
Trade Date			Apr. 01, 2016
Derivative, Inception Date			Jan. 17, 2017
Maturity Date			Dec. 15, 2021
Pay Fixed Swap Rate	1.36%		1.36%
Fair Value	$ 1,227,000		$ 1,227,000
Positions Seven [Member] [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000		$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate	2.34%		2.34%
Trade Date			Apr. 01, 2016
Derivative, Inception Date			Jan. 17, 2017
Maturity Date			Dec. 15, 2021
Pay Fixed Swap Rate	1.36%		1.36%
Fair Value	$ 1,218,000		$ 1,218,000
Position Eight [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000		$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate	2.32%		2.32%
Trade Date			Jul. 18, 2017
Derivative, Inception Date			Aug. 15, 2017
Maturity Date			Aug. 15, 2022
Pay Fixed Swap Rate	1.88%		1.88%
Fair Value	$ 949,000		$ 949,000
Position Nine [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 50,000,000		$ 50,000,000
Receive (Variable) Index			1 Month LIBOR
Current Rate Paid on Derivative for Interest Rate Swaps which qualify as hedges	2.07%		2.07%
Trade Date			Jan. 09, 2018
Derivative, Inception Date			Jan. 16, 2018
Maturity Date			Jan. 15, 2023
Pay Fixed Swap Rate	2.24%		2.24%
Fair Value	$ (1,073,000)		$ (1,073,000)
Position ten [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 50,000,000		$ 50,000,000
Receive (Variable) Index			1 Month LIBOR
Current Rate Paid on Derivative for Interest Rate Swaps which qualify as hedges	2.07%		2.07%
Trade Date			Jan. 09, 2018
Derivative, Inception Date			Jan. 16, 2018
Maturity Date			Jan. 15, 2022
Fair Value	$ (382,000)		$ (382,000)
Derivative, Cap Price	2.75%		2.75%
Derivative, Floor Price	1.80%		1.80%