Fair Value Of Financial Instruments (Schedule Of Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Held-for-sale, Fair Value Disclosure	$ 13,529
Securities Purchased under Agreements to Resell	700,000	$ 700,000
Interest-bearing Deposits in Banks and Other Financial Institutions	689,876	30,631
Cash and due from banks	507,892	438,439
Derivative Assets	41,210	8,349
Deferred Compensation Plan Assets	12,968	12,843
Total Assets	8,721,051	8,884,820
Non-interest bearing deposits	6,980,298	7,158,962
Savings, interest checking and money market deposits	11,685,239	11,499,620
Time open and certificates of deposit	1,658,122
Other borrowings	8,702	1,758
Derivative Liability	13,421	8,074
Deferred Compensation Liability, Current and Noncurrent	12,968	12,843
Fair Value Hierarchy, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Deferred Compensation Plan Assets	12,968	12,843
Total Assets	923,205	949,854
Derivative Liability	0	0
Deferred Compensation Liability, Current and Noncurrent	12,968	12,843
Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	40,627	7,723
Deferred Compensation Plan Assets	0	0
Total Assets	7,697,446	7,861,572
Derivative Liability	13,328	7,951
Deferred Compensation Liability, Current and Noncurrent	0	0
Fair Value Hierarchy, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	583	626
Deferred Compensation Plan Assets	0	0
Total Assets	100,400	73,394
Derivative Liability	93	123
Deferred Compensation Liability, Current and Noncurrent	0	0
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,140,298	13,983,674
Loans Held-for-sale, Fair Value Disclosure	20,694	21,398
Investments, Fair Value Disclosure	8,698,666	8,893,307
Federal funds sold	3,320	42,775
Securities Purchased under Agreements to Resell	700,000	700,000
Interest-bearing Deposits in Banks and Other Financial Institutions	689,876	30,631
Cash and due from banks	507,892	438,439
Derivative Assets	41,210	8,349
Deferred Compensation Plan Assets	12,968	12,843
Total Assets	24,814,924	24,131,416
Non-interest bearing deposits	6,980,298	7,158,962
Savings, interest checking and money market deposits	11,685,239	11,499,620
Time open and certificates of deposit	1,658,122	1,766,864
Federal Funds Purchased, Fair Value Disclosure	13,170	202,370
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	1,943,219	1,304,768
Other borrowings	8,702	1,758
Derivative Liability	13,421	8,074
Deferred Compensation Liability, Current and Noncurrent	12,968	12,843
Financial Liabilities Fair Value Disclosure	22,315,139	21,955,259
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	5,106,427	4,958,554
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	869,659	968,820
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,875,788	2,697,452
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,127,083	2,062,787
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,955,572	2,104,487
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	376,399	400,587
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Consumer Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	814,134	783,864
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	15,236	7,123
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,866,003	13,993,509
Loans Held-for-sale, Fair Value Disclosure	20,694	21,398
Investments, Fair Value Disclosure	8,698,666	8,893,307
Federal funds sold	3,320	42,775
Securities Purchased under Agreements to Resell	693,228	695,194
Interest-bearing Deposits in Banks and Other Financial Institutions	689,876	30,631
Cash and due from banks	507,892	438,439
Derivative Assets	41,210	8,349
Deferred Compensation Plan Assets	12,968	12,843
Total Assets	24,533,857	24,136,445
Non-interest bearing deposits	6,980,298	7,158,962
Savings, interest checking and money market deposits	11,685,239	11,499,620
Time open and certificates of deposit	1,663,748	1,768,780
Federal Funds Purchased, Fair Value Disclosure	13,170	202,370
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	1,944,458	1,305,375
Other borrowings	8,702	1,758
Derivative Liability	13,421	8,074
Deferred Compensation Liability, Current and Noncurrent	12,968	12,843
Financial Liabilities Fair Value Disclosure	22,322,004	21,957,782
Estimate of Fair Value, Fair Value Disclosure [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	5,017,694	4,971,401
Estimate of Fair Value, Fair Value Disclosure [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	868,274	979,389
Estimate of Fair Value, Fair Value Disclosure [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,846,095	2,702,598
Estimate of Fair Value, Fair Value Disclosure [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,084,370	2,060,443
Estimate of Fair Value, Fair Value Disclosure [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,916,627	2,074,129
Estimate of Fair Value, Fair Value Disclosure [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	365,069	400,333
Estimate of Fair Value, Fair Value Disclosure [Member] \| Consumer Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	756,651	798,093
Estimate of Fair Value, Fair Value Disclosure [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	11,223	7,123
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Loans Held-for-sale, Fair Value Disclosure	0	0
Investments, Fair Value Disclosure	910,237	937,011
Federal funds sold	3,320	42,775
Securities Purchased under Agreements to Resell	0	0
Interest-bearing Deposits in Banks and Other Financial Institutions	689,876	30,631
Cash and due from banks	507,892	438,439
Derivative Assets	0	0
Deferred Compensation Plan Assets	12,968	12,843
Total Assets	2,124,293	1,461,699
Non-interest bearing deposits	6,980,298	7,158,962
Savings, interest checking and money market deposits	11,685,239	11,499,620
Time open and certificates of deposit	0	0
Federal Funds Purchased, Fair Value Disclosure	13,170	202,370
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Other borrowings	0	0
Derivative Liability	0	0
Deferred Compensation Liability, Current and Noncurrent	12,968	12,843
Financial Liabilities Fair Value Disclosure	18,691,675	18,873,795
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Consumer Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Loans Held-for-sale, Fair Value Disclosure	20,694	21,398
Investments, Fair Value Disclosure	7,643,290	7,838,522
Federal funds sold	0	0
Securities Purchased under Agreements to Resell	0	0
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Cash and due from banks	0	0
Derivative Assets	40,627	7,723
Deferred Compensation Plan Assets	0	0
Total Assets	7,704,611	7,867,643
Non-interest bearing deposits	0	0
Savings, interest checking and money market deposits	0	0
Time open and certificates of deposit	0	0
Federal Funds Purchased, Fair Value Disclosure	0	0
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Other borrowings	0	0
Derivative Liability	13,328	7,951
Deferred Compensation Liability, Current and Noncurrent	0	0
Financial Liabilities Fair Value Disclosure	13,328	7,951
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Consumer Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,866,003	13,993,509
Loans Held-for-sale, Fair Value Disclosure	0	0
Investments, Fair Value Disclosure	145,139	117,774
Federal funds sold	0	0
Securities Purchased under Agreements to Resell	693,228	695,194
Interest-bearing Deposits in Banks and Other Financial Institutions	0	0
Cash and due from banks	0	0
Derivative Assets	583	626
Deferred Compensation Plan Assets	0	0
Total Assets	14,704,953	14,807,103
Non-interest bearing deposits	0	0
Savings, interest checking and money market deposits	0	0
Time open and certificates of deposit	1,663,748	1,768,780
Federal Funds Purchased, Fair Value Disclosure	0	0
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	1,944,458	1,305,375
Other borrowings	8,702	1,758
Derivative Liability	93	123
Deferred Compensation Liability, Current and Noncurrent	0	0
Financial Liabilities Fair Value Disclosure	3,617,001	3,076,036
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	5,017,694	4,971,401
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	868,274	979,389
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,846,095	2,702,598
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,084,370	2,060,443
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,916,627	2,074,129
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	365,069	400,333
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Consumer Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	756,651	798,093
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	$ 11,223	$ 7,123

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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The amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements.

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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The aggregate of all domestic and foreign interest-bearing deposit liabilities.

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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