Derivative Instruments and Hedging Activities (Impact of Derivatives on Balance Sheet) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Derivatives not designated as hedging instruments
Derivative [Line Items]
Fair value of derivative assets	$ 200,697	$ 320,493
Fair value of derivative liabilities	106,692	157,167
Derivatives not designated as hedging instruments \| Interest rate contracts
Derivative [Line Items]
Notional Amount	9,273,899	8,784,141
Fair value of derivative assets	197,018	314,234
Fair value of derivative liabilities	105,488	153,204
Derivatives not designated as hedging instruments \| Mortgage derivatives \| Mortgage derivatives - interest rate lock commitments
Derivative [Line Items]
Notional Amount	159,858	306,138
Fair value of derivative assets	3,100	6,259
Fair value of derivative liabilities	0	0
Derivatives not designated as hedging instruments \| Mortgage derivatives \| Mortgage derivatives - forward commitments to sell fixed-rate mortgage loans
Derivative [Line Items]
Notional Amount	155,500	230,500
Fair value of derivative assets	579	0
Fair value of derivative liabilities	0	1,611
Derivatives not designated as hedging instruments \| Other contracts
Derivative [Line Items]
Notional Amount	206,365	234,884
Fair value of derivative assets	0	0
Fair value of derivative liabilities	33	304
Derivatives not designated as hedging instruments \| Visa derivative
Derivative [Line Items]
Notional Amount	0	0
Fair value of derivative assets	0	0
Fair value of derivative liabilities	1,171	2,048
Derivatives not designated as hedging instruments \| Risk derivative
Derivative [Line Items]
Notional Amount	56,200	2,600
Cash flow hedges
Derivative [Line Items]
Fair value of derivative assets	44,294	80,802
Fair value of derivative liabilities	3,799	0
Cash flow hedges \| Interest rate contracts
Derivative [Line Items]
Notional Amount	3,600,000	3,000,000
Fair value of derivative assets	44,294	80,802
Fair value of derivative liabilities	$ 3,799	$ 0

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Nominal or face amount used to calculate payment on derivative.

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