Loans - Additional Information (Detail)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2020 USD ($) Loan	Jun. 30, 2021 USD ($) Employee Contract	Dec. 31, 2020 USD ($) Loan	Dec. 27, 2020 USD ($)
Accounts Notes And Loans Receivable [Line Items]
Total Loans		$ 2,019,196,000	$ 2,057,502,000
Net deferred loan fees		6,848,000	5,998,000
Loans processed	$ 0	0
Paycheck Protection Program Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Net deferred loan fees		$ 5,855,000	$ 5,194,000
Number of loans processed		1,340	2,300
Loans processed		$ 131,109,000	$ 268,300,000	$ 284,500,000,000
Number of employees | Employee		300
Percentage of reduction in gross revenues		25.00%
Maximum of monthly payroll allowable amount		$ 2,000,000
Commercial and Agriculture [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans		328,871,000	409,876,000
Number of loans processed | Loan	813
Loans processed	$ 431,300,000
Commercial and Agriculture [Member] | Paycheck Protection Program Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans		$ 153,007,000	$ 217,295,000