Investment Securities - Portfolio of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity, Amortized Cost	$ 67,777	$ 81,052
Gross Unrealized Gains	169	436
Gross Unrealized Losses	1,188	568
Fair Value	66,758	80,920
Obligations of state and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity, Amortized Cost	27,486	35,908
Gross Unrealized Gains	169	265
Gross Unrealized Losses	95	22
Fair Value	27,560	36,151
GSE mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity, Amortized Cost	31,978	35,751
Gross Unrealized Gains	0	171
Gross Unrealized Losses	687	219
Fair Value	31,291	35,703
Collateralized mortgage obligations: residential
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity, Amortized Cost	6,833	7,450
Gross Unrealized Gains	0	0
Gross Unrealized Losses	394	321
Fair Value	6,439	7,129
Collateralized mortgage obligations: commercial
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity, Amortized Cost	1,480	1,943
Gross Unrealized Gains	0	0
Gross Unrealized Losses	12	6
Fair Value	$ 1,468	$ 1,937

Amount of investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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