Derivatives (Fair Values of Derivative Financial Instruments) (Details) - USD ($)		9 Months Ended	12 Months Ended
		Sep. 30, 2025	Dec. 31, 2024
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		$ 7,745,924,000	$ 7,392,532,000
Fair Values, Assets		49,736,000	71,893,000
Fair Values, Assets	[1]	111,539,000	150,253,000
Less: netting adjustment	[1]	(43,383,000)	(76,413,000)	[2]
Total derivative assets/liabilities	[1]	68,156,000	73,840,000
Fair Values, Liabilities		42,453,000	54,707,000
Fair Values, Liabilities	[1]	106,586,000	160,623,000
Less: netting adjustment	[1]	(4,000)
Other Liabilities [Member]
Derivatives Fair Value [Line Items]
Total derivative assets/liabilities	[1]	106,582,000	160,623,000
Derivatives Designated as Hedging Instruments [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		2,122,500,000	1,827,500,000
Fair Values, Assets	[1]	27,683,000	39,647,000
Fair Values, Liabilities	[1]	21,313,000	48,022,000
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		5,623,424,000	5,565,032,000
Fair Values, Assets	[1]	83,856,000	110,606,000
Fair Values, Liabilities	[1]	85,273,000	112,601,000
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		5,021,110,000	4,926,461,000
Fair Values, Assets	[1]	78,218,000	108,702,000
Fair Values, Liabilities	[1]	78,382,000	108,761,000
Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		368,598,000	445,554,000
Fair Values, Assets	[1]	13,000	7,000
Fair Values, Liabilities	[1]	8,000	9,000
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		33,729,000	25,526,000
Fair Values, Assets	[1]	648,000
Fair Values, Liabilities	[1]		383,000
Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		11,311,000	27,465,000
Fair Values, Assets	[1]		420,000
Fair Values, Liabilities	[1]	132,000	0
Derivatives Not Designated as Hedging Instruments [Member] | To Be Announced (TBA) Securities [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		35,750,000	15,250,000
Fair Values, Assets	[1]	92,000	88,000
Fair Values, Liabilities	[1]	70,000	1,000
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		111,184,000	82,756,000
Fair Values, Assets	[1]	4,885,000	1,389,000
Fair Values, Liabilities	[1]	4,826,000	1,358,000
Derivatives Not Designated as Hedging Instruments [Member] | Visa Class B derivative contract [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		41,742,000	42,020,000
Fair Values, Liabilities	[1]	1,855,000	2,089,000
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		1,725,000,000	1,350,000,000
Fair Values, Assets	[1]	4,655,000
Fair Values, Liabilities	[1]	21,313,000	48,022,000
Fair Value Hedging [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps - Securities [Member]
Derivatives Fair Value [Line Items]
Notional or Contractual Amount		397,500,000	477,500,000
Fair Values, Assets	[1]	$ 23,028,000	$ 39,647,000

[1] Derivative assets and liabilities are reported in other assets and 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.