Fair Value Of Financial Instruments (Schedule Of Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands		Jun. 30, 2022	Dec. 31, 2021
Carrying Amount
Fair Value, Balance Sheet Grouping [Line Items]
Loans		$ 15,686,627	$ 15,176,359
Loans held for sale		6,467	8,615
Investment securities		13,947,188	14,695,628
Federal Funds Sold		26,000	2,800
Securities purchased under agreements to resell		1,450,000	1,625,000
Interest earning deposits with banks		684,994	3,971,217
Cash and due from banks		355,524	305,539
Derivative Asset		12,404	41,842
Assets held in trust for deferred compensation plan		17,862	21,794
Assets, Fair Value Financial Instruments		32,187,066	35,848,794
Non-interest bearing deposits		11,102,585	11,772,374
Savings, interest checking and money market deposits		16,063,064	16,598,085
Certificates of deposits		1,005,584	1,442,614
Federal funds purchased		7,750	43,385
Securities sold under agreements to repurchase		2,226,546	2,979,582
Other borrowings		4,390	12,514
Derivative Liabilities		27,599	12,101
Liabilities held in trust for deferred compensation plan		17,862	21,794
Financial Liabilities Fair Value Disclosure		30,455,380	32,882,449
Carrying Amount | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,441,592	5,303,535
Carrying Amount | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,266,260	1,118,266
Carrying Amount | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,215,578	3,058,837
Carrying Amount | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,836,835	2,805,401
Carrying Amount | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,089,592	2,032,225
Carrying Amount | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		271,854	275,945
Carrying Amount | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		558,102	575,410
Carrying Amount | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		6,814	6,740
Estimated Fair Value at June 30, 2022
Fair Value, Balance Sheet Grouping [Line Items]
Loans		15,243,361	15,040,655
Loans held for sale		6,467	8,615
Investment securities		13,947,188	14,695,628
Federal Funds Sold		26,000	2,800
Securities purchased under agreements to resell		1,423,660	1,623,856
Interest earning deposits with banks		684,994	3,971,217
Cash and due from banks		355,524	305,539
Derivative Asset		12,404	41,842
Assets held in trust for deferred compensation plan		17,862	21,794
Assets, Fair Value Financial Instruments		31,717,460	35,711,946
Non-interest bearing deposits		11,102,585	11,772,374
Savings, interest checking and money market deposits		16,063,064	16,598,085
Certificates of deposits		992,566	1,438,919
Federal funds purchased		7,750	43,385
Securities sold under agreements to repurchase		2,227,167	2,979,677
Other borrowings		4,390	12,514
Derivative Liabilities		27,599	12,101
Liabilities held in trust for deferred compensation plan		17,862	21,794
Financial Liabilities Fair Value Disclosure		30,442,983	32,878,849
Estimated Fair Value at June 30, 2022 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,326,823	5,229,153
Estimated Fair Value at June 30, 2022 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,249,488	1,099,747
Estimated Fair Value at June 30, 2022 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,128,428	3,054,481
Estimated Fair Value at June 30, 2022 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,686,693	2,809,490
Estimated Fair Value at June 30, 2022 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,054,657	2,031,408
Estimated Fair Value at June 30, 2022 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		268,543	273,450
Estimated Fair Value at June 30, 2022 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		522,025	536,468
Estimated Fair Value at June 30, 2022 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		6,704	6,458
Estimated Fair Value at June 30, 2022 | Level 1
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Loans held for sale		0	0
Investment securities		1,115,258	1,087,873
Federal Funds Sold		26,000	2,800
Securities purchased under agreements to resell		0	0
Interest earning deposits with banks		684,994	3,971,217
Cash and due from banks		355,524	305,539
Derivative Asset		0	0
Assets held in trust for deferred compensation plan		17,862	21,794
Assets, Fair Value Financial Instruments		2,199,638	5,389,223
Non-interest bearing deposits		11,102,585	11,772,374
Savings, interest checking and money market deposits		16,063,064	16,598,085
Certificates of deposits		0	0
Federal funds purchased		7,750	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		17,862	21,794
Financial Liabilities Fair Value Disclosure		27,191,261	28,435,638
Estimated Fair Value at June 30, 2022 | Level 1 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 1 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 1 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 1 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 1 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 1 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 1 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 1 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Loans held for sale		6,467	8,615
Investment securities		12,623,559	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		12,088	40,994
Assets held in trust for deferred compensation plan		0	0
Assets, Fair Value Financial Instruments		12,642,114	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		4,390	12,514
Derivative Liabilities		27,437	11,824
Liabilities held in trust for deferred compensation plan		0	0
Financial Liabilities Fair Value Disclosure		31,827	24,338
Estimated Fair Value at June 30, 2022 | Level 2 | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2 | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2 | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2 | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2 | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2 | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2 | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Level 2 | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		0	0
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping [Line Items]
Loans		15,243,361	15,040,655
Loans held for sale		0	0
Investment securities		208,371	194,197
Federal Funds Sold		0	0
Securities purchased under agreements to resell		1,423,660	1,623,856
Interest earning deposits with banks		0	0
Cash and due from banks		0	0
Derivative Asset		316	848
Assets held in trust for deferred compensation plan		0	0
Assets, Fair Value Financial Instruments		16,875,708	16,859,556
Non-interest bearing deposits		0	0
Savings, interest checking and money market deposits		0	0
Certificates of deposits		992,566	1,438,919
Federal funds purchased		0	0
Securities sold under agreements to repurchase		2,227,167	2,979,677
Other borrowings		0	0
Derivative Liabilities		162	277
Liabilities held in trust for deferred compensation plan		0	0
Financial Liabilities Fair Value Disclosure		3,219,895	4,418,873
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		5,326,823	5,229,153
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Real estate - construction and land
Fair Value, Balance Sheet Grouping [Line Items]
Loans		1,249,488	1,099,747
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Real estate - business
Fair Value, Balance Sheet Grouping [Line Items]
Loans		3,128,428	3,054,481
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Real estate - personal
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,686,693	2,809,490
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Consumer
Fair Value, Balance Sheet Grouping [Line Items]
Loans		2,054,657	2,031,408
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Revolving home equity
Fair Value, Balance Sheet Grouping [Line Items]
Loans		268,543	273,450
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Consumer credit card
Fair Value, Balance Sheet Grouping [Line Items]
Loans		522,025	536,468
Estimated Fair Value at June 30, 2022 | Significant Unobservable Inputs (Level 3) | Overdrafts
Fair Value, Balance Sheet Grouping [Line Items]
Loans		6,704	6,458
Interest earning deposits with banks		684,994	3,971,217
Cash and due from banks		355,524	305,539
Derivative Asset	[1]	12,404	41,842
Assets held in trust for deferred compensation plan		17,862	21,794
Non-interest bearing deposits		11,102,585	11,772,374
Savings, interest checking and money market deposits		16,063,064	16,598,085
Other borrowings		6,025	12,560
Derivative Liabilities	[1]	27,599	12,101
Liabilities held in trust for deferred compensation plan		17,862	21,794
Level 1
Fair Value, Balance Sheet Grouping [Line Items]
Derivative Asset	[1]	0	0
Assets held in trust for deferred compensation plan		17,862	21,794
Derivative Liabilities	[1]	0	0
Liabilities held in trust for deferred compensation plan		17,862	21,794
Level 2
Fair Value, Balance Sheet Grouping [Line Items]
Derivative Asset	[1]	12,088	40,994
Assets held in trust for deferred compensation plan		0	0
Derivative Liabilities	[1]	27,437	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]	316	848
Assets held in trust for deferred compensation plan		0	0
Derivative Liabilities	[1]	162	277
Liabilities held in trust for deferred compensation plan		$ 0	$ 0

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