Allowance for Credit Losses (Collateral Dependent Loans and Leases) (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 21,779,367
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,210,182
Commercial Real Estate | Non-owner occupied term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,505,802
Commercial Real Estate | Owner Occupied Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,333,945
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,343,857
Commercial | Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,024,467
Commercial | LOC & Other, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	862,760
Commercial | Leases and Equipment Finance, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,456,630
Residential
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,007,970
Residential | Mortgage, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,871,906
Residential | Home Equity Loans & Lines, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,136,064
Residential Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	257,530
Residential Real Estate | Commercial Real Estate | Non-owner occupied term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Residential Real Estate | Commercial Real Estate | Owner Occupied Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Residential Real Estate | Commercial | Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	933
Residential Real Estate | Commercial | LOC & Other, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Residential Real Estate | Commercial | Leases and Equipment Finance, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Residential Real Estate | Residential | Mortgage, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	254,248
Residential Real Estate | Residential | Home Equity Loans & Lines, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,349
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	8,955
Commercial Real Estate | Commercial Real Estate | Non-owner occupied term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,474
Commercial Real Estate | Commercial Real Estate | Owner Occupied Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,432
Commercial Real Estate | Commercial | Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	49
Commercial Real Estate | Commercial | LOC & Other, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Commercial Real Estate | Commercial | Leases and Equipment Finance, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Commercial Real Estate | Residential | Mortgage, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Commercial Real Estate | Residential | Home Equity Loans & Lines, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
General Business Assets
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	19,250
General Business Assets | Commercial Real Estate | Non-owner occupied term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
General Business Assets | Commercial Real Estate | Owner Occupied Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
General Business Assets | Commercial | Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	368
General Business Assets | Commercial | LOC & Other, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	140
General Business Assets | Commercial | Leases and Equipment Finance, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	18,742
General Business Assets | Residential | Mortgage, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
General Business Assets | Residential | Home Equity Loans & Lines, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	986
Other | Commercial Real Estate | Non-owner occupied term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Other | Commercial Real Estate | Owner Occupied Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Other | Commercial | Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	789
Other | Commercial | LOC & Other, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	197
Other | Commercial | Leases and Equipment Finance, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Other | Residential | Mortgage, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Other | Residential | Home Equity Loans & Lines, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Total
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	286,721
Total | Commercial Real Estate | Non-owner occupied term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,474
Total | Commercial Real Estate | Owner Occupied Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,432
Total | Commercial | Term, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,139
Total | Commercial | LOC & Other, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	337
Total | Commercial | Leases and Equipment Finance, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	18,742
Total | Residential | Mortgage, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	254,248
Total | Residential | Home Equity Loans & Lines, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,349