Securities - Summary of Amortized Costs and Fair Values of Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Securities available for sale:
Amortized Cost	$ 102,147	$ 90,594
Gross Unrealized Gains	75	153
Gross Unrealized (Losses)	(2,365)	(1,492)
Fair Value	99,857	89,255
Securities held to maturity:
Amortized Cost	43,408	48,208
Gross Unrealized Gains	29	90
Gross Unrealized (Losses)	(1,043)	(596)
Fair Value	42,394	47,702
Total securities, Amortized cost	145,555	138,802
Total securities, Gross unrealized gains	104	243
Total securities, Gross unrealized (losses)	(3,408)	(2,088)
Total securities, Fair value	142,251	136,957
U.S. agency and mortgage-backed securities
Securities available for sale:
Amortized Cost	86,944	76,074
Gross Unrealized Gains	44	67
Gross Unrealized (Losses)	(2,066)	(1,337)
Fair Value	84,922	74,804
Securities held to maturity:
Amortized Cost	27,420	32,149
Gross Unrealized Gains	0	0
Gross Unrealized (Losses)	(869)	(551)
Fair Value	26,551	31,598
Obligations of states and political subdivisions
Securities available for sale:
Amortized Cost	15,203	14,520
Gross Unrealized Gains	31	86
Gross Unrealized (Losses)	(299)	(155)
Fair Value	14,935	14,451
Securities held to maturity:
Amortized Cost	14,488	14,559
Gross Unrealized Gains	20	74
Gross Unrealized (Losses)	(174)	(45)
Fair Value	14,334	14,588
Corporate debt securities
Securities held to maturity:
Amortized Cost	1,500	1,500
Gross Unrealized Gains	9	16
Gross Unrealized (Losses)	0	0
Fair Value	$ 1,509	$ 1,516

Available for sale and held to maturity securities accumulated gross unrealized loss.

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Available for sale securities and held to maturity securities accumulated gross unrealized gain.

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

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