Fair Value Of Financial Instruments (Schedule Of Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Carrying Amount
Fair Value, Balance Sheet Grouping [Line Items]
Loans		$ 17,298,840	$ 17,205,479
Loans held for sale		2,328	4,177
Investment securities		9,433,421	9,941,786
Federal Funds Sold		0	5,025
Securities purchased under agreements to resell		225,000	450,000
Interest earning deposits with banks		1,609,614	2,239,010
Cash and due from banks		291,040	443,147
Derivative Asset		94,758	116,876
Assets held in trust for deferred compensation plan		21,270	20,538
Assets, Fair Value Financial Instruments		28,976,271	30,426,038
Non-interest bearing deposits		7,513,464	7,975,935
Savings, interest checking and money market deposits		14,463,211	14,512,273
Certificates of deposits		2,463,520	2,875,690
Federal funds purchased		264,470	261,305
Securities sold under agreements to repurchase		2,241,106	2,647,510
Other borrowings		2,327	1,366
Derivative Liabilities		38,546	37,899
Liabilities held in trust for deferred compensation plan		21,270	20,538
Financial Liabilities Fair Value Disclosure		27,007,914	28,332,516
Carrying Amount | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,994,974	6,019,036
Carrying Amount | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,497,647	1,446,764
Carrying Amount | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,711,602	3,719,306
Carrying Amount | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,039,885	3,026,041
Carrying Amount | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,119,308	2,077,723
Carrying Amount | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		322,523	319,894
Carrying Amount | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		564,388	589,913
Carrying Amount | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		48,513	6,802
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping [Line Items]
Loans		16,424,206	16,347,391
Loans held for sale		2,328	4,177
Investment securities		9,433,421	9,941,786
Federal Funds Sold		0	5,025
Securities purchased under agreements to resell		220,549	444,448
Interest earning deposits with banks		1,609,614	2,239,010
Cash and due from banks		291,040	443,147
Derivative Asset		94,758	116,876
Assets held in trust for deferred compensation plan		21,270	20,538
Assets, Fair Value Financial Instruments		28,097,186	29,562,398
Non-interest bearing deposits		7,513,464	7,975,935
Savings, interest checking and money market deposits		14,463,211	14,512,273
Certificates of deposits		2,493,713	2,916,627
Federal funds purchased		264,470	261,305
Securities sold under agreements to repurchase		2,244,279	2,650,951
Other borrowings		2,327	1,366
Derivative Liabilities		38,546	37,899
Liabilities held in trust for deferred compensation plan		21,270	20,538
Financial Liabilities Fair Value Disclosure		27,041,280	28,376,894
Estimate of Fair Value Measurement [Member] | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,844,133	5,873,549
Estimate of Fair Value Measurement [Member] | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,470,405	1,420,522
Estimate of Fair Value Measurement [Member] | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,582,707	3,594,834
Estimate of Fair Value Measurement [Member] | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,565,443	2,568,026
Estimate of Fair Value Measurement [Member] | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,069,841	2,016,334
Estimate of Fair Value Measurement [Member] | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		319,524	317,013
Estimate of Fair Value Measurement [Member] | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		524,843	550,464
Estimate of Fair Value Measurement [Member] | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		47,310	6,649
Estimate of Fair Value Measurement [Member] | Level 1
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Loans held for sale		0	0
Investment securities		755,897	822,237
Federal Funds Sold		0	5,025
Securities purchased under agreements to resell		0	0
Interest earning deposits with banks		1,609,614	2,239,010
Cash and due from banks		291,040	443,147
Derivative Asset		0	0
Assets held in trust for deferred compensation plan		21,270	20,538
Assets, Fair Value Financial Instruments		2,677,821	3,529,957
Non-interest bearing deposits		7,513,464	7,975,935
Savings, interest checking and money market deposits		14,463,211	14,512,273
Certificates of deposits		0	0
Federal funds purchased		264,470	261,305
Securities sold under agreements to repurchase		0	0
Other borrowings		0	0
Derivative Liabilities		0	0
Liabilities held in trust for deferred compensation plan		21,270	20,538
Financial Liabilities Fair Value Disclosure		22,262,415	22,770,051
Estimate of Fair Value Measurement [Member] | Level 1 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 1 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 1 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 1 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 1 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 1 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 1 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 1 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Loans held for sale		2,328	4,177
Investment securities		8,447,422	8,896,129
Federal Funds Sold		0	0
Securities purchased under agreements to resell		0	0
Interest earning deposits with banks		0	0
Cash and due from banks		0	0
Derivative Asset		94,617	116,710
Assets held in trust for deferred compensation plan		0	0
Assets, Fair Value Financial Instruments		8,544,367	9,017,016
Non-interest bearing deposits		0	0
Savings, interest checking and money market deposits		0	0
Certificates of deposits		0	0
Federal funds purchased		0	0
Securities sold under agreements to repurchase		0	0
Other borrowings		2,327	1,366
Derivative Liabilities		38,440	37,704
Liabilities held in trust for deferred compensation plan		0	0
Financial Liabilities Fair Value Disclosure		40,767	39,070
Estimate of Fair Value Measurement [Member] | Level 2 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Level 2 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping [Line Items]
Loans		16,424,206	16,347,391
Loans held for sale		0	0
Investment securities		230,102	223,420
Federal Funds Sold		0	0
Securities purchased under agreements to resell		220,549	444,448
Interest earning deposits with banks		0	0
Cash and due from banks		0	0
Derivative Asset		141	166
Assets held in trust for deferred compensation plan		0	0
Assets, Fair Value Financial Instruments		16,874,998	17,015,425
Non-interest bearing deposits		0	0
Savings, interest checking and money market deposits		0	0
Certificates of deposits		2,493,713	2,916,627
Federal funds purchased		0	0
Securities sold under agreements to repurchase		2,244,279	2,650,951
Other borrowings		0	0
Derivative Liabilities		106	195
Liabilities held in trust for deferred compensation plan		0	0
Financial Liabilities Fair Value Disclosure		4,738,098	5,567,773
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,844,133	5,873,549
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,470,405	1,420,522
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,582,707	3,594,834
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,565,443	2,568,026
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,069,841	2,016,334
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		319,524	317,013
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		524,843	550,464
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		47,310	6,649
Federal Funds Sold		0	5,025
Securities purchased under agreements to resell		225,000	450,000
Interest earning deposits with banks		1,609,614	2,239,010
Cash and due from banks		291,040	443,147
Derivative Asset	[1]	94,758	116,876
Assets held in trust for deferred compensation plan		21,270	20,538
Non-interest bearing deposits		7,513,464	7,975,935
Savings, interest checking and money market deposits		14,463,211	14,512,273
Other borrowings		2,359	1,404
Derivative Liabilities	[1]	38,546	37,899
Liabilities held in trust for deferred compensation plan		21,270	20,538
Level 1
Fair Value, Balance Sheet Grouping [Line Items]
Derivative Asset	[1]	0	0
Assets held in trust for deferred compensation plan		21,270	20,538
Derivative Liabilities	[1]	0	0
Liabilities held in trust for deferred compensation plan		21,270	20,538
Level 2
Fair Value, Balance Sheet Grouping [Line Items]
Derivative Asset	[1]	94,617	116,710
Assets held in trust for deferred compensation plan		0	0
Derivative Liabilities	[1]	38,440	37,704
Liabilities held in trust for deferred compensation plan		0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping [Line Items]
Derivative Asset	[1]	141	166
Assets held in trust for deferred compensation plan		0	0
Derivative Liabilities	[1]	106	195
Liabilities held in trust for deferred compensation plan		$ 0	$ 0

[1] * The fair value of each class of derivative is shown in Note 11.