Available for Sale Securities - Summary of Amortized Costs and Fair Values of Securities Available-for-sale, by Contractual Maturity (Detail) $ in Thousands	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	$ 1,255
Due after one through 5 years	5,419
Due after 5 through 10 years	1,435
Due after 10 years	5,274
Subtotal	13,383
Total	58,703
Due in one year or less	1,239
Due after one through 5 years	5,217
Due after 5 through 10 years	1,326
Due after 10 years	5,246
Subtotal	13,028
Total	57,145
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Subtotal	38,039
Subtotal	36,886
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Subtotal	7,281
Subtotal	$ 7,231