Purchased Loans - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 USD ($) loan
Financing Receivable, Allowance for Credit Loss [Line Items]
Outstanding balance of restructured loans	$ 9,856,743,000	$ 10,757,503,000
Restructured loans discontinued past due period	90 days
Allowance for credit losses on interest deferred	$ 164,171,000	$ 176,144,000	$ 52,162,000
Purchased loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonperforming loans charged off past due period	90 days
Number of restructured loans | loan	1	1
Restructured loans discontinued past due period	90 days	90 days
Modifications, recorded investment	$ 5,609,000	$ 8,687,000	7,275,000
Modifications, subsequent default, recorded investment	0	74,000	$ 101,000
Remaining availability under commitments to lend additional funds on restructured loans	$ 2,000	$ 370,000
Number of loans on deferral | loan	3	13	5
Deferral amount	$ 1,161,000	$ 5,262,000	$ 2,931,000
Purchased loans | Payment Deferral | Loan Deferral Program, CARES Act
Financing Receivable, Allowance for Credit Loss [Line Items]
Number of loans on deferral | loan	2
Deferral amount	$ 76,000
Purchased loans | Nonaccruing Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Outstanding balance of restructured loans	36,000	74,000
Purchased loans | Restructured Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Outstanding balance of restructured loans	10,380,000	12,788,000
Allowance for credit losses on interest deferred	$ 104,000	$ 612,000