Cash Value of Life Insurance - Summary of Activity in Balance of Cash Value of Life Insurance (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) company employee policy	Dec. 31, 2020 USD ($) employee company policy	Dec. 31, 2019 USD ($)
Insurance [Line Items]
Beginning balance	$ 118,870	$ 117,823
Increase in cash value of life insurance	2,775	2,949	$ 3,029
Gain on death benefit	702	498	831
Insurance proceeds receivable reclassified to other assets	(4,490)	(2,400)
Ending balance	117,857	118,870	$ 117,823
End of period death benefit	$ 193,318	$ 197,379
Number of policies owned (in policies) | policy	176	183
Insurance companies used (in companies) | company	14	14
Current and former employees and directors covered (in employees) | employee	59	62
FNBB
Insurance [Line Items]
Acquired policies from business combination	$ 0	$ 0