Loans - Schedule of Average Recorded Investment in Impaired Loans and Related Interest Income Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Average recorded investment:
Average recorded investment in impaired loans	$ 1,799	$ 6,113
Interest income recognized:
Interest income recognized on a cash basis on impaired loans	13	50
Commercial [Member]
Average recorded investment:
Average recorded investment in impaired loans	264	2,025
Interest income recognized:
Interest income recognized on a cash basis on impaired loans	1	10
Commercial Real Estate [Member]
Average recorded investment:
Average recorded investment in impaired loans	222	2,814
Interest income recognized:
Interest income recognized on a cash basis on impaired loans	2	30
Residential Real Estate [Member]
Average recorded investment:
Average recorded investment in impaired loans	849	810
Interest income recognized:
Interest income recognized on a cash basis on impaired loans	8	8
Construction & Land Development [Member]
Average recorded investment:
Average recorded investment in impaired loans	329	325
Consumer [Member]
Average recorded investment:
Average recorded investment in impaired loans	135	139
Interest income recognized:
Interest income recognized on a cash basis on impaired loans	$ 2	$ 2