Investment Securities - Summary of Interest Income on Available-For-Sale Investment Securities (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Total taxable interest income	$ 3,136	$ 2,650
Total tax-exempt interest income	281	213
Total interest income	3,417	2,863
U.S. Treasury and government sponsored entities
Schedule of Available-for-sale Securities [Line Items]
Total taxable interest income	2,255	1,979
U.S. Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Total taxable interest income	0	4
Other
Schedule of Available-for-sale Securities [Line Items]
Total taxable interest income	881	667
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Total tax-exempt interest income	$ 281	$ 213

Amount of operating dividend and interest income, including amortization and accretion of premiums and discounts, on securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.2,3)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e24721-111560

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