Securities Available-for-sale - Summary of Amortized Costs and Fair Value of Securities Available-for-sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	$ 69,555	$ 90,035
Securities Available for Sale, Gross Unrealized Gains	31	325
Securities Available for Sale, Gross Unrealized Losses	(2,711)	(1,405)
Securities Available for Sale, Fair Value	66,875	88,955
Obligations of States and Political Subdivisions [Member]
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	11,482	20,545
Securities Available for Sale, Gross Unrealized Gains	17	243
Securities Available for Sale, Gross Unrealized Losses	(298)	(158)
Securities Available for Sale, Fair Value	11,201	20,630
Government-sponsored Mortgage-backed Securities [Member]
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	53,543	61,218
Securities Available for Sale, Gross Unrealized Gains	3	41
Securities Available for Sale, Gross Unrealized Losses	(2,410)	(1,235)
Securities Available for Sale, Fair Value	51,136	60,024
Corporate Collateralized Mortgage Obligations [Member]
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	437	696
Securities Available for Sale, Gross Unrealized Gains	2	6
Securities Available for Sale, Fair Value	439	702
Asset-backed Securities [Member]
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	3,844	4,835
Securities Available for Sale, Gross Unrealized Gains	9	9
Securities Available for Sale, Gross Unrealized Losses		(12)
Securities Available for Sale, Fair Value	3,853	4,832
Corporate Bond [Member]
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost		1,246
Securities Available for Sale, Gross Unrealized Gains		5
Securities Available for Sale, Fair Value		1,251
Certificates of Deposit [Member]
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	249	1,495
Securities Available for Sale, Gross Unrealized Gains		21
Securities Available for Sale, Gross Unrealized Losses	(3)
Securities Available for Sale, Fair Value	$ 246	$ 1,516

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

No definition available.

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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