Fair Values - Recurring and Nonrecurring (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	$ 298,812,000	$ 317,535,000	$ 305,589,000
Equity Securities	1,850,000	1,774,000	1,579,000
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	298,812,000	317,535,000	305,589,000
Equity Securities	1,850,000	1,774,000	1,579,000
Total Securities Measured on a Recurring Basis	300,662,000	319,309,000	307,168,000
Fair Value, Measurements, Recurring | Quoted Prices In Active Markets for Indentical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0
Equity Securities	0	0	0
Total Securities Measured on a Recurring Basis	0	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	298,812,000	317,535,000	305,589,000
Equity Securities	1,850,000	1,774,000	1,579,000
Total Securities Measured on a Recurring Basis	300,662,000	319,309,000	307,168,000
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0
Equity Securities	0	0	0
Total Securities Measured on a Recurring Basis	0	0	0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	684,000	0	1,295,000
Collateral Dependent Impaired Loans, Life-to-Date Gains (Losses)	0	0	(58,000)
Other Real Estate Owned and Repossessed Assets, Net	1,445,000	1,260,000	1,647,000
Other Real Estate owned and Repossessed Assets, Net, Life-to-Date Gains (Losses)	(826,000)	(669,000)	(582,000)
Fair Value, Measurements, Nonrecurring | Quoted Prices In Active Markets for Indentical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	0	0	0
Other Real Estate Owned and Repossessed Assets, Net	0	0	0
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	0	0	0
Other Real Estate Owned and Repossessed Assets, Net	0	0	0
Fair Value, Measurements, Nonrecurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	684,000	0	1,295,000
Other Real Estate Owned and Repossessed Assets, Net	1,445,000	1,260,000	1,647,000
U.S. Agency Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	35,383,000	46,765,000	59,657,000
U.S. Agency Obligations | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	35,383,000	46,765,000	59,657,000
U.S. Agency Obligations | Fair Value, Measurements, Recurring | Quoted Prices In Active Markets for Indentical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0	0	0
U.S. Agency Obligations | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	35,383,000	46,765,000	59,657,000
U.S. Agency Obligations | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0	0	0
State and Municipal Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	1,116,000	1,195,000	9,743,000
State and Municipal Obligations | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	1,116,000	1,195,000	9,743,000
State and Municipal Obligations | Fair Value, Measurements, Recurring | Quoted Prices In Active Markets for Indentical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0	0	0
State and Municipal Obligations | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	1,116,000	1,195,000	9,743,000
State and Municipal Obligations | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0	0	0
Mortgage-Backed Securities - Residential | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	261,513,000	268,775,000	235,389,000
Mortgage-Backed Securities - Residential | Fair Value, Measurements, Recurring | Quoted Prices In Active Markets for Indentical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0	0	0
Mortgage-Backed Securities - Residential | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	261,513,000	268,775,000	235,389,000
Mortgage-Backed Securities - Residential | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0	0	0
Corporate and Other Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	800,000	800,000	800,000
Corporate and Other Debt Securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	800,000	800,000	800,000
Corporate and Other Debt Securities | Fair Value, Measurements, Recurring | Quoted Prices In Active Markets for Indentical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	0	0	0
Corporate and Other Debt Securities | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	800,000	800,000	800,000
Corporate and Other Debt Securities | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	$ 0	$ 0	$ 0