Derivatives and Hedging Activities (Derivative Positions for Interest Rate Swaps which Qualify as Hedges) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 75,000,000		$ 75,000,000
Fair Value	836,000		624,000
Amortization Of Deferred Hedge Gains Losses	61,000	$ 61,000	244,000
Change in Fair Value on Loans Held for Sale	(147,000)	$ 54,000	87,000
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
Trade Date			Dec. 09, 2008
Effective Date			Dec. 10, 2008
Maturity Date			Dec. 10, 2018
Current Rate Received			0.95%
Pay Fixed Swap Rate			2.94%
Fair Value			$ (740,000)
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
Trade Date			Apr. 01, 2016
Effective Date			Jan. 17, 2017
Maturity Date			Dec. 15, 2021
Pay Fixed Swap Rate			1.36%
Fair Value			$ 689,000
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
Trade Date			Apr. 01, 2016
Effective Date			Jan. 17, 2017
Maturity Date			Dec. 15, 2021
Pay Fixed Swap Rate			1.36%
Fair Value			$ 675,000
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
Trade Date	Dec. 09, 2008
Effective Date	Dec. 10, 2008
Maturity Date	Dec. 10, 2018
Current Rate Received	1.11%
Pay Fixed Swap Rate	2.94%
Fair Value	$ (600,000)
Positions Five [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
Trade Date	Apr. 01, 2016
Effective Date	Jan. 17, 2017
Maturity Date	Dec. 15, 2021
Current Rate Received	1.13%
Pay Fixed Swap Rate	1.36%
Fair Value	$ 726,000
Positions Six [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
Trade Date	Apr. 01, 2016
Effective Date	Jan. 17, 2017
Maturity Date	Dec. 15, 2021
Current Rate Received	1.13%
Pay Fixed Swap Rate	1.36%
Fair Value	$ 710,000