Loans and Allowance for Credit Losses for Loans - Summary of Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 34,153,657	$ 32,217,112
Commercial and industrial *
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,847,551	6,861,708
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	20,790,066	18,470,823
Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	18,935,486	16,724,998
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	4,545,064	4,183,743
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,970,976	2,700,838
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	400,779	431,553
Collateral Pledged
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	241,258	176,027
Collateral Pledged | Commercial and industrial *
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	95,335	106,239
Collateral Pledged | Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	110,174	41,562
Collateral Pledged | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	35,745	28,176
Collateral Pledged | Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 4	$ 50