Loans (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for loan losses:
Beginning Balance				$ 8,540				$ 8,481				$ 8,138	$ 8,540	$ 8,481	$ 8,138
Charge-offs													(1,169)	(1,458)	(2,642)
Recoveries													130	84	332
Provisions	$ 670	$ 698	$ 564	427	$ 362	$ 501	$ 392	178	$ 1,502	$ 385	$ 563	203	2,359	1,433	2,653
Ending Balance	9,860				8,540				8,481				9,860	8,540	8,481
Commercial Real Estate Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				3,465				3,528				3,051	3,465	3,528	3,051
Charge-offs														(78)	(195)
Recoveries													58	17	11
Provisions													1,689	(2)	661
Ending Balance	5,212				3,465				3,528				5,212	3,465	3,528
Residential First Mortgages Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				584				1,047				1,343	584	1,047	1,343
Charge-offs														(30)	(94)
Recoveries														1	186
Provisions													822	(434)	(388)
Ending Balance	1,406				584				1,047				1,406	584	1,047
Residential Rentals Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				538				593				532	538	593	532
Charge-offs													(14)		(155)
Provisions													(162)	(55)	216
Ending Balance	362				538				593				362	538	593
Construction And Land Development Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				1,103				1,071				584	1,103	1,071	584
Charge-offs													(526)		(992)
Recoveries													1	32	84
Provisions													363		1,395
Ending Balance	941				1,103				1,071				941	1,103	1,071
Home Equity And Second Mortgages Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				142				173				249	142	173	249
Charge-offs														(100)	(59)
Recoveries													5		10
Provisions													(9)	69	(27)
Ending Balance	138				142				173				138	142	173
Commercial Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				1,477				1,677				1,916	1,477	1,677	1,916
Charge-offs													(594)	(432)	(1,134)
Recoveries													18	11	5
Provisions													(107)	221	890
Ending Balance	794				1,477				1,677				794	1,477	1,677
Consumer Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				2				3				10	2	3	10
Charge-offs													(1)		(3)
Recoveries															11
Provisions													2	(1)	(15)
Ending Balance	3				2				3				3	2	3
Commercial Equipment Portfolio Segment [Member]
Allowance for loan losses:
Beginning Balance				$ 1,229				$ 389				$ 453	1,229	389	453
Charge-offs													(34)	(818)	(10)
Recoveries													48	23	25
Provisions													(239)	1,635	(79)
Ending Balance	$ 1,004				$ 1,229				$ 389				$ 1,004	$ 1,229	$ 389