Condensed Parent Company Financial Information - Summary of Condensed Statements of Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrealized gain (loss) on equity securities													$ 28	$ (4)	$ 9
Other income													1,181	906	879
NET INCOME	$ 2,306	$ 2,901	$ 2,745	$ 2,885	$ 2,679	$ 2,800	$ 2,606	$ 2,483	$ 2,593	$ 2,695	$ 2,586	$ 2,540	10,837	10,568	10,414
COMPREHENSIVE INCOME													7,726	11,482	11,898
Parent Company [Member]
Dividends on securities													3	3	3
Dividends from subsidiary													4,150	4,140	3,170
Unrealized gain (loss) on equity securities													28	(4)	9
Other income														4
Total income													4,181	4,143	3,182
Operating expenses													341	357	357
Income before taxes and undistributed equity income of subsidiary													3,840	3,786	2,825
Income tax benefit													(65)	(76)	(73)
Equity earnings in subsidiary, net of dividends													6,932	6,706	7,516
NET INCOME													10,837	10,568	10,414
COMPREHENSIVE INCOME													$ 7,726	$ 11,482	$ 11,898