Fair Value of Financial Instruments Fair Value - Recurring and Nonrecurring (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	$ 305,589	$ 300,200	$ 347,159
Equity Securities	1,579	0	0
Available-for-sale Securities, Amortized Cost Basis	311,038	301,876	347,701
With a Related Allowance		1,543	288
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	305,589	300,200	347,159
Equity Securities	1,579
Total Securities Measured on a Recurring Basis	307,168
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	59,657	59,894	54,695
Equity Securities	0
Total Securities Measured on a Recurring Basis	59,657
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	245,932	240,306	292,464
Equity Securities	1,579
Total Securities Measured on a Recurring Basis	247,511
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
Equity Securities	0
Total Securities Measured on a Recurring Basis	0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans	1,622	0
Gain (Loss) on Collateral Dependent Impaired Loans		0
Other Real Estate and Repossessed Assets, Net	1,647	1,847	1,734
Gain (Loss) Other Real Estate and Repossessed Assets, Net	(582)	(569)	(500)
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	1,647	1,847	1,734
U.S. Agency Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	59,657	59,894	147,231
Available-for-sale Securities, Amortized Cost Basis	60,264	60,328	147,012
U.S. Agency Obligations | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	59,657	59,894	147,231
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		59,894	54,695
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	0	92,536
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	9,743	10,349	25,507
Available-for-sale Securities, Amortized Cost Basis	9,741	10,351	25,467
State and Municipal Obligations | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale	9,743	10,349	25,507
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	9,743	10,349	25,507
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	235,389	227,596	169,728
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	235,389	227,596	169,728
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	800	3,298
Available-for-sale Securities, Amortized Cost Basis	1,000	1,000	3,501
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	800	3,298
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	800	3,298
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
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale		1,561	1,395
Available-for-sale Securities, Amortized Cost Basis		1,120	1,120
Equity Securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale		1,561
Equity Securities			1,395
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]
Available-for-Sale		0
Equity Securities			0
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]
Available-for-Sale		1,561
Equity Securities			1,395
Equity 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
Equity Securities			0
Collateral Pledged | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans	1,295		288
Gain (Loss) on Collateral Dependent Impaired Loans	(58)		(34)
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	$ 1,295		$ 288