Income Taxes - Schedule of Difference Between Provision for Income Taxes and Amounts Computed by Applying Statutory Federal Income Tax Rate to Income Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax at federal statutory rate	$ 4,725	$ 1,171
State income taxes, net of federal tax effect	34
Tax-exempt interest income	(20)	(74)
Income from life insurance	(82)	(196)
Merger-related expenses	174	188
Other permanent differences	(31)	(116)
Provision for income taxes	$ 4,800	$ 973
Income tax at federal statutory rate	21.00%	21.00%
State income taxes, net of federal tax effect	0.20%
Tax-exempt interest income	(0.10%)	(1.30%)
Income from life insurance	(0.40%)	(3.50%)
Merger-related expenses	0.80%	3.40%
Other permanent differences	(0.10%)	(2.20%)
Provision for income taxes	21.40%	17.40%