Fair Value Of Financial Instruments (Schedule Of Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping [Line Items]
Interest earning deposits with banks		$ 1,260,813	$ 3,971,217
Cash and due from banks		326,549	305,539
Derivative Asset	[1]	13,130	41,842
Assets held in trust for deferred compensation plan		20,403	21,794
Non-interest bearing deposits		11,428,372	11,772,374
Savings, interest checking and money market deposits		16,751,632	16,598,085
Other borrowings		9,057	12,560
Derivative Liabilities	[1]	18,382	12,101
Liabilities held in trust for deferred compensation plan		20,403	21,794
Level 1
Fair Value, Balance Sheet Grouping [Line Items]
Derivative Asset	[1]	0	0
Assets held in trust for deferred compensation plan		20,403	21,794
Derivative Liabilities	[1]	0	0
Liabilities held in trust for deferred compensation plan		20,403	21,794
Level 2
Fair Value, Balance Sheet Grouping [Line Items]
Derivative Asset	[1]	12,760	40,994
Assets held in trust for deferred compensation plan		0	0
Derivative Liabilities	[1]	18,233	11,824
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]	370	848
Assets held in trust for deferred compensation plan		0	0
Derivative Liabilities	[1]	149	277
Liabilities held in trust for deferred compensation plan		0	0
Carrying Amount
Fair Value, Balance Sheet Grouping [Line Items]
Loans		15,459,014	15,176,359
Loans held for sale		8,908	8,615
Investment securities		15,016,882	14,695,628
Federal Funds Sold		0	2,800
Securities purchased under agreements to resell		1,825,000	1,625,000
Interest earning deposits with banks		1,260,813	3,971,217
Cash and due from banks		326,549	305,539
Derivative Asset		13,130	41,842
Assets held in trust for deferred compensation plan		20,403	21,794
Assets, Fair Value Financial Instruments		33,930,699	35,848,794
Non-interest bearing deposits		11,428,372	11,772,374
Savings, interest checking and money market deposits		16,751,632	16,598,085
Certificates of deposits		1,139,337	1,442,614
Federal funds purchased		17,315	43,385
Securities sold under agreements to repurchase		2,300,146	2,979,582
Other borrowings		8,990	12,514
Derivative Liabilities		18,382	12,101
Liabilities held in trust for deferred compensation plan		20,403	21,794
Financial Liabilities Fair Value Disclosure		31,684,577	32,882,449
Carrying Amount | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,508,508	5,303,535
Carrying Amount | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,144,411	1,118,266
Carrying Amount | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,109,668	3,058,837
Carrying Amount | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,820,076	2,805,401
Carrying Amount | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,053,160	2,032,225
Carrying Amount | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		264,401	275,945
Carrying Amount | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		544,579	575,410
Carrying Amount | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		14,211	6,740
Estimated Fair Value at March 31, 2022
Fair Value, Balance Sheet Grouping [Line Items]
Loans		15,201,994	15,040,655
Loans held for sale		8,908	8,615
Investment securities		15,016,882	14,695,628
Federal Funds Sold		0	2,800
Securities purchased under agreements to resell		1,801,227	1,623,856
Interest earning deposits with banks		1,260,813	3,971,217
Cash and due from banks		326,549	305,539
Derivative Asset		13,130	41,842
Assets held in trust for deferred compensation plan		20,403	21,794
Assets, Fair Value Financial Instruments		33,649,906	35,711,946
Non-interest bearing deposits		11,428,372	11,772,374
Savings, interest checking and money market deposits		16,751,632	16,598,085
Certificates of deposits		1,124,978	1,438,919
Federal funds purchased		17,315	43,385
Securities sold under agreements to repurchase		2,300,267	2,979,677
Other borrowings		8,990	12,514
Derivative Liabilities		18,382	12,101
Liabilities held in trust for deferred compensation plan		20,403	21,794
Financial Liabilities Fair Value Disclosure		31,670,339	32,878,849
Estimated Fair Value at March 31, 2022 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,406,516	5,229,153
Estimated Fair Value at March 31, 2022 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,129,894	1,099,747
Estimated Fair Value at March 31, 2022 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,059,118	3,054,481
Estimated Fair Value at March 31, 2022 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,777,860	2,809,490
Estimated Fair Value at March 31, 2022 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,043,692	2,031,408
Estimated Fair Value at March 31, 2022 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		261,985	273,450
Estimated Fair Value at March 31, 2022 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		508,944	536,468
Estimated Fair Value at March 31, 2022 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		13,985	6,458
Estimated Fair Value at March 31, 2022 | Level 1
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Loans held for sale		0	0
Investment securities		1,136,827	1,087,873
Federal Funds Sold		0	2,800
Securities purchased under agreements to resell		0	0
Interest earning deposits with banks		1,260,813	3,971,217
Cash and due from banks		326,549	305,539
Derivative Asset		0	0
Assets held in trust for deferred compensation plan		20,403	21,794
Assets, Fair Value Financial Instruments		2,744,592	5,389,223
Non-interest bearing deposits		11,428,372	11,772,374
Savings, interest checking and money market deposits		16,751,632	16,598,085
Certificates of deposits		0	0
Federal funds purchased		17,315	43,385
Securities sold under agreements to repurchase		0	0
Other borrowings		0	0
Derivative Liabilities		0	0
Liabilities held in trust for deferred compensation plan		20,403	21,794
Financial Liabilities Fair Value Disclosure		28,217,722	28,435,638
Estimated Fair Value at March 31, 2022 | Level 1 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 1 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 1 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 1 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 1 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 1 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 1 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 1 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Loans held for sale		8,908	8,615
Investment securities		13,680,011	13,413,558
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		12,760	40,994
Assets held in trust for deferred compensation plan		0	0
Assets, Fair Value Financial Instruments		13,701,679	13,463,167
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		8,990	12,514
Derivative Liabilities		18,233	11,824
Liabilities held in trust for deferred compensation plan		0	0
Financial Liabilities Fair Value Disclosure		27,223	24,338
Estimated Fair Value at March 31, 2022 | Level 2 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Level 2 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping [Line Items]
Loans		15,201,994	15,040,655
Loans held for sale		0	0
Investment securities		200,044	194,197
Federal Funds Sold		0	0
Securities purchased under agreements to resell		1,801,227	1,623,856
Interest earning deposits with banks		0	0
Cash and due from banks		0	0
Derivative Asset		370	848
Assets held in trust for deferred compensation plan		0	0
Assets, Fair Value Financial Instruments		17,203,635	16,859,556
Non-interest bearing deposits		0	0
Savings, interest checking and money market deposits		0	0
Certificates of deposits		1,124,978	1,438,919
Federal funds purchased		0	0
Securities sold under agreements to repurchase		2,300,267	2,979,677
Other borrowings		0	0
Derivative Liabilities		149	277
Liabilities held in trust for deferred compensation plan		0	0
Financial Liabilities Fair Value Disclosure		3,425,394	4,418,873
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,406,516	5,229,153
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,129,894	1,099,747
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,059,118	3,054,481
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,777,860	2,809,490
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,043,692	2,031,408
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		261,985	273,450
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		508,944	536,468
Estimated Fair Value at March 31, 2022 | Significant Unobservable Inputs (Level 3) | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		$ 13,985	$ 6,458

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