Fair Value Measurements, Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		$ 145,857	$ 157,121
Loans, net of allowances for loan losses	[1]	723,144	729,092
Loans held for sale		715	779
Obligations of U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		9,337	9,435
Obligations of State and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		59,269	64,765
Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		70,941	74,296
Money Market Investments [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		1,612	1,194
Other Marketable Equity Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale			197
Recurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		145,857	157,121
Recurring [Member] | Obligations of U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		9,337	9,435
Recurring [Member] | Obligations of State and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		59,269	64,765
Recurring [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		70,941	74,296
Recurring [Member] | Money Market Investments [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		1,612	1,194
Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		4,698	7,234
Recurring [Member] | Other Marketable Equity Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale			197
Nonrecurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		720
Loans held for sale		715	779
Nonrecurring [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Other real estate owned		203
Nonrecurring [Member] | Mortgage Loans on Real Estate [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		620	567
Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Residential 1-4 Family [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		45	264
Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		272
Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Construction [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		74	74
Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Equity Lines of Credit [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		229	229
Nonrecurring [Member] | Consumer [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		100
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Loans, net of allowances for loan losses	[1]	0	0
Loans held for sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring [Member] | Obligations of U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring [Member] | Obligations of State and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring [Member] | Money Market Investments [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring [Member] | Other Marketable Equity Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale			0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0
Loans held for sale		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Other real estate owned		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Residential 1-4 Family [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Construction [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Equity Lines of Credit [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonrecurring [Member] | Consumer [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		145,857	157,121
Loans, net of allowances for loan losses	[1]	0	0
Loans held for sale		715	779
Significant Other Observable Inputs (Level 2) [Member] | Recurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		145,857	157,121
Significant Other Observable Inputs (Level 2) [Member] | Recurring [Member] | Obligations of U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		9,337	9,435
Significant Other Observable Inputs (Level 2) [Member] | Recurring [Member] | Obligations of State and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		59,269	64,765
Significant Other Observable Inputs (Level 2) [Member] | Recurring [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		70,941	74,296
Significant Other Observable Inputs (Level 2) [Member] | Recurring [Member] | Money Market Investments [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		1,612	1,194
Significant Other Observable Inputs (Level 2) [Member] | Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		4,698	7,234
Significant Other Observable Inputs (Level 2) [Member] | Recurring [Member] | Other Marketable Equity Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale			197
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0
Loans held for sale		715	779
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Other real estate owned		0
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Residential 1-4 Family [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Construction [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Equity Lines of Credit [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0	0
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring [Member] | Consumer [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Loans, net of allowances for loan losses	[1]	705,413	722,464
Loans held for sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Recurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Recurring [Member] | Obligations of U.S. Government Agencies [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Recurring [Member] | Obligations of State and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Recurring [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Recurring [Member] | Money Market Investments [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Recurring [Member] | Other Marketable Equity Securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Securities available-for-sale			0
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		720
Loans held for sale		0	0
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Other real estate owned		203
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		620	567
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Residential 1-4 Family [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		45	264
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Commercial [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		272
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Construction [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		74	74
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member] | Mortgage Loans on Real Estate [Member] | Equity Lines of Credit [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		229	$ 229
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring [Member] | Consumer [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Alternative [Abstract]
Loans, net of allowances for loan losses		$ 100

[1] In accordance with the adoption of ASU 2016-01, the fair values of loans held for investment and time deposits as of March 31, 2018 were measured using an exit price notion. The fair values of loans held for investment and time deposits as of December 31, 2017 were measured using an entry price notion.