Loans and Allowance for Credit Losses for Loans - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans net of unearned discount and deferred loan fees	$ 125,400,000		$ 120,500,000
Accrued interest	192,600,000		175,900,000
Sales of loans	0	$ 0
TDRs not reported as non-accrual loans			56,500,000
Non-performing TDRs			104,700,000
Specific reserves for loan losses		$ 7,800,000
Other real estate owned	1,200,000		286,000
Allowance for purchase credit deteriorated (PCD) loans	(22,300,000)
Residential real estate properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other real estate owned	0		0
In formal foreclosure proceedings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential mortgage and consumer loans secured by residential real estate properties	$ 1,500,000		$ 2,600,000