Fair Value Measurements, Measured On A Recurring And Nonrecurring Basis (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Fair value assets and liabilities measured on non-recurring basis [Abstract]
Impaired loans, estimated selling cost	$ 246	$ 188
Recurring [Member]
Securities available for sale [Abstract]
U.S. agency securities	132,551	170,414
U.S. treasury securities		3,000
Obligations of state and political subdivisions	81,723	96,926
Corporate obligations	3,101	3,050
Mortgage-backed securities in government sponsored entities	44,277	37,728
Equity securities in financial institutions	1,936	2,899
Recurring [Member] | Level I [Member]
Securities available for sale [Abstract]
U.S. agency securities	0	0
U.S. treasury securities		3,000
Obligations of state and political subdivisions	0	0
Corporate obligations	0	0
Mortgage-backed securities in government sponsored entities	0	0
Equity securities in financial institutions	1,936	2,899
Recurring [Member] | Level II [Member]
Securities available for sale [Abstract]
U.S. agency securities	132,551	170,414
U.S. treasury securities		0
Obligations of state and political subdivisions	81,723	96,926
Corporate obligations	3,101	3,050
Mortgage-backed securities in government sponsored entities	44,277	37,728
Equity securities in financial institutions	0	0
Recurring [Member] | Level III [Member]
Securities available for sale [Abstract]
U.S. agency securities	0	0
U.S. treasury securities		0
Obligations of state and political subdivisions	0	0
Corporate obligations	0	0
Mortgage-backed securities in government sponsored entities	0	0
Equity securities in financial institutions	0	0
Nonrecurring [Member]
Fair value assets and liabilities measured on non-recurring basis [Abstract]
Impaired Loans	3,024	2,033
Other real estate owned	1,478	839
Nonrecurring [Member] | Level I [Member]
Fair value assets and liabilities measured on non-recurring basis [Abstract]
Impaired Loans	0	0
Other real estate owned	0	0
Nonrecurring [Member] | Level II [Member]
Fair value assets and liabilities measured on non-recurring basis [Abstract]
Impaired Loans	0	0
Other real estate owned	0	0
Nonrecurring [Member] | Level III [Member]
Fair value assets and liabilities measured on non-recurring basis [Abstract]
Impaired Loans	3,024	2,033
Other real estate owned	$ 1,478	$ 839