Investment Securities, Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Available-for-Sale:
Amortized Cost	$ 330,303	$ 324,662
Unrealized Gains	1,548	1,129
Unrealized Losses	3,063	5,132
Fair Value	328,788	320,659
Held-to-Maturity:
Amortized Cost	38,437	41,003
Unrealized Gains	95	56
Unrealized Losses	246	569
Fair Value	38,286	40,490
U.S. Treasury notes [Member]
Available-for-Sale:
Amortized Cost	21,135	28,180
Unrealized Gains	77	41
Unrealized Losses	3	76
Fair Value	21,209	28,145
U.S. Agency notes [Member]
Available-for-Sale:
Amortized Cost	96,921	87,098
Unrealized Gains	161	150
Unrealized Losses	1,134	1,848
Fair Value	95,948	85,400
U.S. Agency mortgage-backed securities [Member]
Available-for-Sale:
Amortized Cost	74,949	72,402
Unrealized Gains	73	89
Unrealized Losses	1,061	1,444
Fair Value	73,961	71,047
Held-to-Maturity:
Amortized Cost	0
Fair Value	0
Non-taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	111,651	114,064
Unrealized Gains	902	574
Unrealized Losses	758	1,623
Fair Value	111,795	113,015
Held-to-Maturity:
Amortized Cost	33,282	31,015
Unrealized Gains	95	56
Unrealized Losses	122	352
Fair Value	33,255	30,719
Taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	22,420	19,710
Unrealized Gains	246	220
Unrealized Losses	63	85
Fair Value	22,603	19,845
Held-to-Maturity:
Amortized Cost	5,155	9,988
Unrealized Gains	0	0
Unrealized Losses	124	217
Fair Value	5,031	9,771
Mutual funds [Member]
Available-for-Sale:
Amortized Cost	2,546	2,527
Unrealized Gains	0	0
Unrealized Losses	39	45
Fair Value	2,507	2,482
Held-to-Maturity:
Amortized Cost	0
Fair Value	0
Trust preferred securities [Member]
Available-for-Sale:
Amortized Cost	49	49
Unrealized Gains	1	0
Unrealized Losses	0	1
Fair Value	50	48
Held-to-Maturity:
Amortized Cost	0
Fair Value	0
Equity securities [Member]
Available-for-Sale:
Amortized Cost	632	632
Unrealized Gains	88	55
Unrealized Losses	5	10
Fair Value	715	$ 677
Held-to-Maturity:
Amortized Cost	0
Fair Value	$ 0