Investment Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Available-for-Sale:
Amortized Cost	$ 356,605	$ 283,661
Unrealized Gains	4,616	3,710
Unrealized Losses	480	2,006
Available-for-sale, at fair value	360,741	285,365
Investment Securities Held-to-Maturity:
Amortized Cost	24,575	22,725
Unrealized Gains	178	108
Unrealized Losses	114	695
Fair Value	24,639	22,138
U.S. Treasury notes [Member]
Available-for-Sale:
Amortized Cost	89,925	62,406
Unrealized Gains	1,211	290
Unrealized Losses	4	136
Available-for-sale, at fair value	91,132	62,560
U.S. Agency notes [Member]
Available-for-Sale:
Amortized Cost	111,825	84,661
Unrealized Gains	701	188
Unrealized Losses	128	1,212
Available-for-sale, at fair value	112,398	83,637
U.S. Agency mortgage-backed securities [Member]
Available-for-Sale:
Amortized Cost	26,119	37,838
Unrealized Gains	331	413
Unrealized Losses	122	219
Available-for-sale, at fair value	26,328	38,032
Investment Securities Held-to-Maturity:
Fair Value	0
Certificates of deposit [Member]
Available-for-Sale:
Amortized Cost	2,084	3,076
Unrealized Gains	2	10
Unrealized Losses	0	0
Available-for-sale, at fair value	2,086	3,086
Non-taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	98,114	75,727
Unrealized Gains	1,766	1,972
Unrealized Losses	111	304
Available-for-sale, at fair value	99,769	77,395
Investment Securities Held-to-Maturity:
Amortized Cost	23,975	22,525
Unrealized Gains	178	108
Unrealized Losses	112	695
Fair Value	24,041	21,938
Taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	25,109	16,005
Unrealized Gains	550	465
Unrealized Losses	18	75
Available-for-sale, at fair value	25,641	16,395
Investment Securities Held-to-Maturity:
Amortized Cost	600	200
Unrealized Gains	0	0
Unrealized Losses	2	0
Fair Value	598	200
Mutual funds [Member]
Available-for-Sale:
Amortized Cost	2,509	2,483
Unrealized Gains	0	0
Unrealized Losses	29	22
Available-for-sale, at fair value	2,480	2,461
Investment Securities Held-to-Maturity:
Fair Value	0
Trust preferred securities [Member]
Available-for-Sale:
Amortized Cost	49	50
Unrealized Gains	0	0
Unrealized Losses	0	0
Available-for-sale, at fair value	49	50
Investment Securities Held-to-Maturity:
Fair Value	0
Equity securities [Member]
Available-for-Sale:
Amortized Cost	871	1,415
Unrealized Gains	55	372
Unrealized Losses	68	38
Available-for-sale, at fair value	858	$ 1,749
Investment Securities Held-to-Maturity:
Fair Value	$ 0

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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