Securities - Additional Information (Detail)			12 Months Ended
	Dec. 31, 2021 USD ($) Security	Apr. 01, 2014 USD ($) Security	Dec. 31, 2021 USD ($) Security	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Investments, Debt and Equity Securities [Abstract]
Number of securities | Security	475	319	475
Aggregate fair value of securities	$ 490,200,000	$ 167,100,000	$ 490,200,000
Gain/Loss from net unrealized holdings, Net of tax	6,000,000	$ 1,300,000	(24,117,000)	$ 24,424,000	$ 16,693,000
Unrealized gain or loss, Held to maturity			0
Allowance for credit losses for available for sale debt securities	0		0	0
Accrued interest receivable on available for sale debt securities	14,600,000		14,600,000	8,100,000
Tax effect of the proceeds from sale of securities			192,000	$ 902,000	$ (16,000)
Pledged of Fair Value of Securities as collateral	146,500,000		146,500,000
Amortization cost of securities as Collateral not Separately Reported	145,000,000		145,000,000
Debt Instrument Repurchase Agreement	130,800,000		130,800,000
Securities Pledged for Federal Home Loan Bank At Fair Value	479,500,000		479,500,000
Securities for Federal Home Loan Bank Not Separately Reported	453,600,000		453,600,000
Debt Instrument Federal Home Loan Bank	0		0
Securities Pledged For Derivative At Fair Value	37,200,000		37,200,000
Securities Pledged For Derivative At Amortized Cost	36,600,000		36,600,000
Debt Instrument Derivative Swap Agreement	$ 7,200,000		$ 7,200,000