Derivatives (Fair Values of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2023	Dec. 31, 2022
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		$ 7,690,027	$ 7,936,239
Fair Values, Assets		$ 127,529	$ 110,734
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other Assets	Other Assets
Fair Values, Assets	[1]	$ 231,692	$ 219,935
Less: netting adjustment	[1],[2]	(107,261)	(110,438)
Total derivative assets/liabilities	[1]	124,431	109,497
Fair Values, Liabilities		122,171	32,601
Fair Values, Liabilities	[1]	307,669	285,592
Less: netting adjustment	[1],[2]		(81,471)
Other Liabilities [Member]
Derivatives Fair Value [Line Items]
Total derivative assets/liabilities	[1]	307,669	204,121
Derivatives Designated as Hedging Instruments [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		2,063,500	2,816,000
Fair Values, Assets	[1]	39,902	45,802
Fair Values, Liabilities	[1]	117,363	112,262
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		5,626,527	5,120,239
Fair Values, Assets	[1]	191,790	174,133
Fair Values, Liabilities	[1]	190,306	173,330
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		5,078,764	4,620,544
Fair Values, Assets	[1]	190,288	172,242
Fair Values, Liabilities	[1]	187,752	169,712
Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		338,165	298,729
Fair Values, Assets	[1]	9	1
Fair Values, Liabilities	[1]	11	13
Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		31,013	13,819
Fair Values, Assets	[1]		161
Fair Values, Liabilities	[1]	174	8
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate-Lock Commitments on Residential Mortgage Loans [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		15,136	10,930
Fair Values, Assets	[1]	351	8
Fair Values, Liabilities	[1]	2	113
Derivatives Not Designated as Hedging Instruments [Member] | To Be Announced (TBA) Securities [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		22,000	10,000
Fair Values, Assets	[1]	177	78
Fair Values, Liabilities	[1]	2	7
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		98,759	123,106
Fair Values, Assets	[1]	965	1,643
Fair Values, Liabilities	[1]	933	1,594
Derivatives Not Designated as Hedging Instruments [Member] | Visa Class B derivative contract [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		42,690	43,111
Fair Values, Liabilities	[1]	1,432	1,883
Cash Flow Hedge [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps - Variable Rate Loans [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		1,550,000	2,100,000
Fair Values, Assets	[1]		2,301
Fair Values, Liabilities	[1]	$ 117,363	$ 112,262
Fair Value Hedging [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps - Variable Rate Loans [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other Assets	Other Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Other Liabilities	Other Liabilities
Fair Value Hedging [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps - Securities [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		$ 513,500	$ 716,000
Fair Values, Assets	[1]	$ 39,902	$ 43,501
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other Assets	Other Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Other Liabilities	Other Liabilities

[1] Derivative assets and liabilities are reported at fair value in other assets or other liabilities, respectively, in the consolidated balance sheets.

[2] Represents balance sheet netting of derivative assets and liabilities for variation margin collateral held or placed with the same central clearing counterparty. See offsetting assets and liabilities for further information.