Securities - Summary of Amortized Cost and Fair Value by Contractual Maturity of Available for Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]
Due in one year or less, Amortized Cost	$ 10,557	$ 10,528
Due after one year but less than five years, Amortized Cost	48,326	49,586
Due after five years but less than ten years, Amortized Cost	19,989	33,332
Due after ten years, Amortized Cost	6,996	5,448
Amortized Cost	85,868	98,894
Due in one year or less, Fair Value	10,578	10,563
Due after one year but less than five years, Fair Value	49,718	49,921
Due after five years but less than ten years, Fair Value	20,453	33,535
Due after ten years, Fair Value	7,104	5,435
Total available-for-sale securities, Fair Value	$ 87,853	$ 99,454	[1]

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