Securities - Securities in Unrealized Loss Positions (Detail) $ in Thousands	Sep. 30, 2020 USD ($) Security	Dec. 31, 2019 USD ($) Security
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | Security	14	39
Less than 12 months, Fair Value	$ 10,266	$ 12,966
Less than 12 months, Unrealized Loss	(107)	(56)
12 months or more, Fair Value		16,930
12 months or more, Unrealized Loss		(125)
Fair Value, Total	10,266	29,896
Total Unrealized Loss	$ (107)	$ (181)
US Government Agencies and Mortgage Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | Security	4	38
Less than 12 months, Fair Value	$ 392	$ 12,356
Less than 12 months, Unrealized Loss	(5)	(53)
12 months or more, Fair Value		16,930
12 months or more, Unrealized Loss		(125)
Fair Value, Total	392	29,286
Total Unrealized Loss	$ (5)	$ (178)
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | Security	9
Less than 12 months, Fair Value	$ 8,680
Less than 12 months, Unrealized Loss	(91)
Fair Value, Total	8,680
Total Unrealized Loss	$ (91)
State and Municipal Obligations
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | Security	1	1
Less than 12 months, Fair Value	$ 1,194	$ 610
Less than 12 months, Unrealized Loss	(11)	(3)
Fair Value, Total	1,194	610
Total Unrealized Loss	$ (11)	$ (3)