Investment Securities, Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-Sale:
Amortized Cost	$ 311,629	$ 324,662
Unrealized Gains	1,463	1,129
Unrealized Losses	2,688	5,132
Fair Value	310,404	320,659
Held-to-Maturity:
Amortized Cost	36,860	41,003
Unrealized Gains	112	56
Unrealized Losses	167	569
Fair Value	36,805	40,490
U.S. Treasury notes [Member]
Available-for-Sale:
Amortized Cost	16,112	28,180
Unrealized Gains	44	41
Unrealized Losses	4	76
Fair Value	16,152	28,145
U.S. Agency notes [Member]
Available-for-Sale:
Amortized Cost	87,862	87,098
Unrealized Gains	119	150
Unrealized Losses	1,035	1,848
Fair Value	86,946	85,400
U.S. Agency mortgage-backed securities [Member]
Available-for-Sale:
Amortized Cost	71,541	72,402
Unrealized Gains	70	89
Unrealized Losses	890	1,444
Fair Value	70,721	71,047
Held-to-Maturity:
Amortized Cost	0
Fair Value	0
Non-taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	110,517	114,064
Unrealized Gains	889	574
Unrealized Losses	683	1,623
Fair Value	110,723	113,015
Held-to-Maturity:
Amortized Cost	33,160	31,015
Unrealized Gains	112	56
Unrealized Losses	38	352
Fair Value	33,234	30,719
Taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	22,398	19,710
Unrealized Gains	259	220
Unrealized Losses	35	85
Fair Value	22,622	19,845
Held-to-Maturity:
Amortized Cost	3,700	9,988
Unrealized Gains	0	0
Unrealized Losses	129	217
Fair Value	3,571	9,771
Mutual funds [Member]
Available-for-Sale:
Amortized Cost	2,576	2,527
Unrealized Gains	1	0
Unrealized Losses	38	45
Fair Value	2,539	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	574	632
Unrealized Gains	80	55
Unrealized Losses	3	10
Fair Value	651	$ 677
Held-to-Maturity:
Amortized Cost	0
Fair Value	$ 0