Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Income Taxes [Line Items]
Federal statutory tax rate			21.00%
Income tax expense	$ 12,095,000	$ 11,641,000	$ 34,359,000	$ 33,770,000
Effective tax rates on pre-tax income	16.93%	16.50%	16.35%	16.39%
Initial capital contribution commitment			$ 5,500,000
Initial contribution included in other assets			131,000		$ 55,000
Leveraged loan, invest in other borrowings	$ 21,053,000		$ 21,053,000
Investment related liabilities		$ 0		$ 0
NMTC Investments [Member]
Income Taxes [Line Items]
Tax Benefit Percent of Qualified Investments			0.39
Investment related liabilities	0		$ 0
FFB Paris Investment Fund, LLC [Member]
Income Taxes [Line Items]
Initial contribution included in other assets			29,000,000		29,000,000
Loan investment	18,000,000		18,000,000		18,000,000
Leveraged loan, invest in other borrowings	$ 21,053,000		$ 21,053,000		$ 21,053,000