Investment Securities, Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-Sale:
Amortized Cost	$ 275,081	$ 278,629
Unrealized Gains	281	608
Unrealized Losses	7,468	4,024
Fair Value	267,894	275,213
Debt Securities, Held-to-Maturity:
Amortized Cost	32,502	32,571
Unrealized Gains	31	101
Unrealized Losses	811	322
Fair Value	31,722	32,350
Equity Securities, Amortized Cost Basis	2,140	2,110
Equity Securities, Accumulated Gross Unrealized Gain, before Tax		100
Equity Securities, Accumulated Gross Unrealized Loss, before Tax		50
Equity Securities	2,144	2,160
U.S. Treasury notes [Member]
Debt Securities, Available-for-Sale:
Amortized Cost	2,281	2,283
Unrealized Gains	0	0
Unrealized Losses	63	24
Fair Value	2,218	2,259
U.S. Agency notes [Member]
Debt Securities, Available-for-Sale:
Amortized Cost	84,806	84,837
Unrealized Gains	4	57
Unrealized Losses	2,900	1,633
Fair Value	81,910	83,261
U.S. Agency mortgage-backed securities [Member]
Debt Securities, Available-for-Sale:
Amortized Cost	65,412	68,347
Unrealized Gains	23	33
Unrealized Losses	2,212	1,227
Fair Value	63,223	67,153
Non-taxable Municipal securities [Member]
Debt Securities, Available-for-Sale:
Amortized Cost	102,625	102,849
Unrealized Gains	131	343
Unrealized Losses	2,050	1,018
Fair Value	100,706	102,174
Debt Securities, Held-to-Maturity:
Amortized Cost	28,802	28,871
Unrealized Gains	31	101
Unrealized Losses	614	227
Fair Value	28,219	28,745
Taxable Municipal securities [Member]
Debt Securities, Available-for-Sale:
Amortized Cost	19,957	20,313
Unrealized Gains	123	175
Unrealized Losses	243	122
Fair Value	19,837	20,366
Debt Securities, Held-to-Maturity:
Amortized Cost	3,700	3,700
Unrealized Gains	0	0
Unrealized Losses	197	95
Fair Value	3,503	3,605
Mutual funds [Member]
Debt Securities, Held-to-Maturity:
Equity Securities, Amortized Cost Basis	1,613	1,586
Equity Securities, Accumulated Gross Unrealized Gain, before Tax		2
Equity Securities, Accumulated Gross Unrealized Loss, before Tax		46
Equity Securities	1,548	1,542
Trust preferred securities [Member]
Debt Securities, Held-to-Maturity:
Equity Securities, Amortized Cost Basis	49	49
Equity Securities, Accumulated Gross Unrealized Gain, before Tax		1
Equity Securities, Accumulated Gross Unrealized Loss, before Tax		0
Equity Securities	50	50
Equity securities [Member]
Debt Securities, Held-to-Maturity:
Equity Securities, Amortized Cost Basis	478	475
Equity Securities, Accumulated Gross Unrealized Gain, before Tax		97
Equity Securities, Accumulated Gross Unrealized Loss, before Tax		4
Equity Securities	$ 546	$ 568