Loans and Allowance for Credit Losses for Loans - Additional Information (Details) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 01, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans net of unearned discount and deferred loan fees		$ 141,200,000		$ 141,200,000		$ 78,500,000
Non covered loans net of earned discount and deferred loan fees		98,600,000		98,600,000
Payments to Acquire Loans Held-for-investment				5,900,000,000
Accrued interest		115,700,000		115,700,000		83,700,000
Sales of loans				$ 0	$ 0
Number of consecutive months for performing restructured loans to be put on accrual status				6 months
TDRs not reported as non-accrual loans		67,300,000		$ 67,300,000		71,300,000
Non-performing TDRs		154,400,000		154,400,000		117,200,000
Specific reserves for loan losses		56,000,000	$ 4,500,000	56,000,000	4,500,000
Loan charge-offs related to loans modified as TDRs		1,500,000	$ 697,000	1,500,000	$ 5,800,000
Other real estate owned		422,000		422,000		2,300,000
Allowance for purchase credit deteriorated (PCD) loans						115,300,000
Allowance for purchase credit deteriorated (PCD) loans	$ 70,319,000	70,319,000		70,319,000
Financing receivable, excluding accrued interest, not purchased with credit deterioration, credit loss, expense (reversal)				41,000,000
Residential real estate properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other real estate owned		0		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		$ 2,000,000		$ 2,000,000		$ 2,500,000