Loans and Allowance for Credit Losses for Loans - Summary of Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 35,364,405	$ 34,153,657
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,791,390	5,847,551
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	21,937,744	20,790,066
Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	19,763,202	18,935,486
Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,174,542	1,854,580
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	4,691,935	4,545,064
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,943,336	2,970,976
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	393,538	400,779
Collateral Pledged
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	230,805	241,258
Collateral Pledged | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	93,389	95,335
Collateral Pledged | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	111,709	110,174
Collateral Pledged | Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	92,402	110,174
Collateral Pledged | Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	19,307	0
Collateral Pledged | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	25,704	35,745
Collateral Pledged | Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 3	$ 4