Investment Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Available-for-Sale:
Amortized Cost	$ 346,084	$ 377,267
Unrealized Gains	5,209	2,739
Unrealized Losses	192	2,028
Available-for-sale, at fair value	351,101	377,978
Investment Securities Held-to-Maturity:
Amortized Cost	36,505	22,633
Unrealized Gains	535	95
Unrealized Losses	92	98
Fair Value	36,948	22,630
U.S. Treasury notes [Member]
Available-for-Sale:
Amortized Cost	52,591	72,672
Unrealized Gains	1,001	309
Unrealized Losses	0	135
Available-for-sale, at fair value	53,592	72,846
U.S. Agency notes [Member]
Available-for-Sale:
Amortized Cost	126,835	140,876
Unrealized Gains	1,473	164
Unrealized Losses	6	1,151
Available-for-sale, at fair value	128,302	139,889
U.S. Agency mortgage-backed securities [Member]
Available-for-Sale:
Amortized Cost	33,561	29,608
Unrealized Gains	281	174
Unrealized Losses	74	404
Available-for-sale, at fair value	33,768	29,378
Investment Securities Held-to-Maturity:
Fair Value	0
Certificates of deposit [Member]
Available-for-Sale:
Amortized Cost	248	248
Unrealized Gains	1	1
Unrealized Losses	0	0
Available-for-sale, at fair value	249	249
Non-taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	102,900	103,900
Unrealized Gains	1,798	1,713
Unrealized Losses	56	134
Available-for-sale, at fair value	104,642	105,479
Investment Securities Held-to-Maturity:
Amortized Cost	29,873	22,233
Unrealized Gains	528	95
Unrealized Losses	78	97
Fair Value	30,323	22,231
Taxable Municipal securities [Member]
Available-for-Sale:
Amortized Cost	26,714	26,738
Unrealized Gains	596	337
Unrealized Losses	5	134
Available-for-sale, at fair value	27,305	26,941
Investment Securities Held-to-Maturity:
Amortized Cost	6,632	400
Unrealized Gains	7	0
Unrealized Losses	14	1
Fair Value	6,625	399
Mutual funds [Member]
Available-for-Sale:
Amortized Cost	2,527	2,517
Unrealized Gains	0	0
Unrealized Losses	35	51
Available-for-sale, at fair value	2,492	2,466
Investment Securities Held-to-Maturity:
Fair Value	0
Trust preferred securities [Member]
Available-for-Sale:
Amortized Cost	49	49
Unrealized Gains	0	1
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	659	659
Unrealized Gains	59	40
Unrealized Losses	16	19
Available-for-sale, at fair value	702	$ 680
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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