Securities - Aggregate Amortized Costs and Fair Values of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 85,868	$ 98,894
Gross Unrealized Gains	2,092	741
Gross Unrealized (Losses)	(107)	(181)
Fair Value	87,853	99,454	[1]
US Government Agencies and Mortgage Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	47,598	67,491
Gross Unrealized Gains	1,277	284
Gross Unrealized (Losses)	(5)	(178)
Fair Value	48,870	67,597
State and Municipal Obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,116	16,238
Gross Unrealized Gains	741	341
Gross Unrealized (Losses)	(11)	(3)
Fair Value	18,846	16,576
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,154	15,165
Gross Unrealized Gains	74	116
Gross Unrealized (Losses)	(91)
Fair Value	$ 20,137	$ 15,281

[1] Derived from audited December 31, 2019 Consolidated Financial Statements.