Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial Assets
Securities available for sale	$ 389,996	$ 392,937
Loan yield maintenance provisions	1,167	653
Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	396,888	398,516
Loan yield maintenance provisions	1,167	653
Corporate bonds
Financial Assets
Securities available for sale	1,183	1,234
Corporate bonds | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	1,183	1,234
Collateralized mortgage obligations | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	21,301	17,121
Small Business Administration
Financial Assets
Securities available for sale	12,427	14,212
Small Business Administration | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	12,427	14,212
Other investments measured at net asset value | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	6,465	5,185
U.S. Treasury and U.S. government sponsored entities
Financial Assets
Securities available for sale	6,383	8,917
U.S. Treasury and U.S. government sponsored entities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	6,383	8,917
State and political subdivisions
Financial Assets
Securities available for sale	201,275	191,003
State and political subdivisions | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	201,275	191,003
Mortgage-backed securities - residential
Financial Assets
Securities available for sale	147,427	160,450
Mortgage-backed securities - residential | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	147,427	160,450
Equity securities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	427	394
Interest rate swaps | Fair Value, Measurements, Recurring
Financial Liabilities
Derivative liabilities	1,167	653
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	427	394
Loan yield maintenance provisions	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Collateralized mortgage obligations | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Small Business Administration | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury and U.S. government sponsored entities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | State and political subdivisions | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage-backed securities - residential | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	427	394
Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate swaps | Fair Value, Measurements, Recurring
Financial Liabilities
Derivative liabilities	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	389,990	392,929
Loan yield maintenance provisions	1,167	653
Significant Other Observable Inputs (Level 2) | Corporate bonds | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	1,183	1,234
Significant Other Observable Inputs (Level 2) | Collateralized mortgage obligations | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	21,301	17,121
Significant Other Observable Inputs (Level 2) | Small Business Administration | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	12,427	14,212
Significant Other Observable Inputs (Level 2) | U.S. Treasury and U.S. government sponsored entities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	6,383	8,917
Significant Other Observable Inputs (Level 2) | State and political subdivisions | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	201,275	191,003
Significant Other Observable Inputs (Level 2) | Mortgage-backed securities - residential | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	147,421	160,442
Significant Other Observable Inputs (Level 2) | Equity securities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Significant Other Observable Inputs (Level 2) | Interest rate swaps | Fair Value, Measurements, Recurring
Financial Liabilities
Derivative liabilities	1,167	653
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	6	8
Loan yield maintenance provisions	0	0
Significant Unobservable Inputs (Level 3) | Corporate bonds | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Collateralized mortgage obligations | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Small Business Administration | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | U.S. Treasury and U.S. government sponsored entities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | State and political subdivisions | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Mortgage-backed securities - residential | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	6	8
Significant Unobservable Inputs (Level 3) | Equity securities | Fair Value, Measurements, Recurring
Financial Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Interest rate swaps | Fair Value, Measurements, Recurring
Financial Liabilities
Derivative liabilities	$ 0	$ 0