Investment Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	$ 155,122	$ 44,438
Held to maturity, Fair Value	156,149	45,097
Held-to-maturity, Gross Unrealized Gains	1,175	820
Held-to-maturity, Gross Unrealized Losses	(148)	(161)
Available-for-sale, Amortized Cost	257,468	378,254
Available-for-sale, at fair value	258,092	372,580
Available-for-sale, Gross Unrealized Gains	1,477	575
Available-for-sale, Gross Unrealized Losses	(853)	(6,249)
Total investment securities, Amortized Cost	412,590	422,692
Total investment securities, Fair Value	414,241	417,677
Total investment securities, Gross Unrealized Gains	2,652	1,395
Total investment securities, Gross Unrealized Losses	(1,001)	(6,410)
MBS pass-through securities issued by FHLMC and FNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	91,404	193,998
Available-for-sale, at fair value	91,716	190,566
Available-for-sale, Gross Unrealized Gains	551	145
Available-for-sale, Gross Unrealized Losses	(239)	(3,577)
CMOs issued by FNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	11,504	13,790
Available-for-sale, at fair value	11,529	13,772
Available-for-sale, Gross Unrealized Gains	68	91
Available-for-sale, Gross Unrealized Losses	(43)	(109)
CMOs issued by FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	35,317	43,452
Available-for-sale, at fair value	35,360	42,758
Available-for-sale, Gross Unrealized Gains	56	37
Available-for-sale, Gross Unrealized Losses	(13)	(731)
CMOs issued by GNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	8,754	6,844
Available-for-sale, at fair value	8,765	6,945
Available-for-sale, Gross Unrealized Gains	62	102
Available-for-sale, Gross Unrealized Losses	(51)	(1)
Debentures of government- sponsored agencies
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	30,492	35,486
Available-for-sale, at fair value	30,382	35,403
Available-for-sale, Gross Unrealized Gains	0	7
Available-for-sale, Gross Unrealized Losses	(110)	(90)
Privately issued CMOs
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	127	419
Available-for-sale, at fair value	128	419
Available-for-sale, Gross Unrealized Gains	1	1
Available-for-sale, Gross Unrealized Losses	0	(1)
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	74,903	79,306
Available-for-sale, at fair value	75,181	77,701
Available-for-sale, Gross Unrealized Gains	675	135
Available-for-sale, Gross Unrealized Losses	(397)	(1,740)
Corporate bonds
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	4,967	4,959
Available-for-sale, at fair value	5,031	5,016
Available-for-sale, Gross Unrealized Gains	64	57
Available-for-sale, Gross Unrealized Losses	0	0
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	20,213	30,856
Held to maturity, Fair Value	20,790	31,544
Held-to-maturity, Gross Unrealized Gains	577	694
Held-to-maturity, Gross Unrealized Losses	0	(6)
Corporate bonds
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	0	3,519
Held to maturity, Fair Value	0	3,518
Held-to-maturity, Gross Unrealized Gains	0	0
Held-to-maturity, Gross Unrealized Losses	0	(1)
MBS pass-through securities issued by FHLMC and FNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	103,624	10,063
Held to maturity, Fair Value	103,904	10,035
Held-to-maturity, Gross Unrealized Gains	425	126
Held-to-maturity, Gross Unrealized Losses	(145)	(154)
CMOs issued by FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	31,285	0
Held to maturity, Fair Value	31,455	0
Held-to-maturity, Gross Unrealized Gains	173	0
Held-to-maturity, Gross Unrealized Losses	$ (3)	$ 0

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Fair Value of Available-for-sale Securities and Held-to-maturity Securities.

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

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

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