Fair Value of Financial Instruments Fair Value - Recurring and Nonrecurring (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	$ 325,387,000	$ 300,200,000	$ 327,392,000
Equity Securities	1,802,000	0	0
Securities Available-for-Sale		300,200,000	327,392,000
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	325,387,000
Equity Securities	1,802,000
Total Securities Measured on a Recurring Basis	327,189,000
Securities Available-for-Sale		300,200,000	327,392,000
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	59,615,000
Equity Securities	0
Total Securities Measured on a Recurring Basis	59,615,000
Securities Available-for-Sale		59,894,000	54,676,000
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	265,772,000
Equity Securities	1,802,000
Total Securities Measured on a Recurring Basis	267,574,000
Securities Available-for-Sale		240,306,000	272,716,000
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
Total Securities Measured on a Recurring Basis	0
Securities Available-for-Sale		0	0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans		0
Gain (Loss) on Collateral Dependent Impaired Loans		0
Other Real Estate and Repossessed Assets, Net	1,487,000	1,847,000	1,613,000
Gain (Loss) Other Real Estate and Repossessed Assets, Net	(654,000)	(569,000)	(584,000)
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]
Impaired Loans		0
Other Real Estate 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]
Impaired Loans		0
Other Real Estate 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]
Impaired Loans		0
Other Real Estate and Repossessed Assets, Net	1,487,000	1,847,000	1,613,000
U.S. Agency Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	59,615,000
Securities Available-for-Sale		59,894,000	147,085,000
U.S. Agency Obligations | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	59,615,000
Securities Available-for-Sale		59,894,000	147,085,000
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	59,615,000
Securities Available-for-Sale		59,894,000	54,676,000
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	0
Securities Available-for-Sale		0	92,409,000
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
Securities Available-for-Sale		0	0
State and Municipal Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	3,383,000
Securities Available-for-Sale		10,349,000	15,441,000
State and Municipal Obligations | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	3,383,000
Securities Available-for-Sale		10,349,000	15,441,000
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
Securities Available-for-Sale		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	3,383,000
Securities Available-for-Sale		10,349,000	15,441,000
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
Securities Available-for-Sale		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	261,589,000
Securities Available-for-Sale		227,596,000	161,077,000
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
Securities Available-for-Sale		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	261,589,000
Securities Available-for-Sale		227,596,000	161,077,000
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
Securities Available-for-Sale		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
Securities Available-for-Sale		800,000	2,299,000
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
Securities Available-for-Sale		800,000	2,299,000
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
Securities Available-for-Sale		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
Securities Available-for-Sale		800,000	2,299,000
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
Securities Available-for-Sale		0	0
Mutual Funds and Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities Available-for-Sale		1,561,000	1,490,000
Mutual Funds and Equity Securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities			1,490,000
Securities Available-for-Sale		1,561,000
Mutual Funds and Equity 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]
Equity Securities			0
Securities Available-for-Sale		0
Mutual Funds and Equity Securities | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities			1,490,000
Securities Available-for-Sale		1,561,000
Mutual Funds and Equity Securities | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities			0
Securities Available-for-Sale		$ 0
Collateral Pledged | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans	747,000		791,000
Gain (Loss) on Collateral Dependent Impaired Loans	(58,000)		(146,000)
Collateral Pledged | 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]
Impaired Loans	0		0
Collateral Pledged | Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans	0		0
Collateral Pledged | Fair Value, Measurements, Nonrecurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans	$ 747,000		$ 791,000