Loans and Allowance for Loan Losses - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Total loans	$ 12,182,203	$ 12,281,510
Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total loans	2,886,560	2,960,527
Commercial Portfolio Segment | Business Banking
Financing Receivable, Past Due [Line Items]
Total loans	$ 1,201,007	1,334,694
Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		9,040,062
Nonperforming Loans | Unrated
Financing Receivable, Past Due [Line Items]
Total loans		872,544
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total loans		2,960,527
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Unrated
Financing Receivable, Past Due [Line Items]
Total loans		171,537
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Unrated | Paycheck Protection Program
Financing Receivable, Past Due [Line Items]
Total loans		112,800
Nonperforming Loans | Commercial Portfolio Segment | Business Banking
Financing Receivable, Past Due [Line Items]
Total loans		1,334,694
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Unrated
Financing Receivable, Past Due [Line Items]
Total loans		696,629
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Unrated | Paycheck Protection Program
Financing Receivable, Past Due [Line Items]
Total loans		$ 218,600