Loans, Loan Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Loans and Leases Receivable [Line Items]
Loans	$ 24,224,949	$ 24,451,724
PPP
Loans and Leases Receivable [Line Items]
Loans	66,070	767,757
Commercial Finance and Asset Based Lending
Loans and Leases Receivable [Line Items]
Loans	178,027	137,476
Commercial and industrial
Loans and Leases Receivable [Line Items]
Loans	8,208,289	7,563,945
Commercial real estate - owner occupied
Loans and Leases Receivable [Line Items]
Loans	971,326	900,912
Commercial and business lending
Loans and Leases Receivable [Line Items]
Loans	9,423,711	9,370,091
Commercial real estate - investor
Loans and Leases Receivable [Line Items]
Loans	4,384,569	4,342,584
Real estate construction
Loans and Leases Receivable [Line Items]
Loans	1,808,976	1,840,417
Commercial real estate lending
Loans and Leases Receivable [Line Items]
Loans	6,193,545	6,183,001
Total commercial
Loans and Leases Receivable [Line Items]
Loans	15,617,256	15,553,091
Residential mortgage
Loans and Leases Receivable [Line Items]
Loans	7,567,310	7,878,324
Home equity
Loans and Leases Receivable [Line Items]
Loans	595,615	707,255
Other consumer
Loans and Leases Receivable [Line Items]
Loans	301,723	301,876
Auto
Loans and Leases Receivable [Line Items]
Loans	143,045	11,177
Total consumer
Loans and Leases Receivable [Line Items]
Loans	$ 8,607,693	$ 8,898,632