Fair Value Of Financial Instruments (Schedule Of Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value of Personal Real Estate Loans Held for Sale	$ 11,300
Available for sale securities	9,109,287	$ 9,649,203
Trading securities	24,605	22,225
Non-marketable	99,268	99,558
Securities purchased under agreements to resell	700,000	725,000
Cash and due from banks	461,724	494,690
Derivative Assets	11,650	13,566
Assets held in trust for deferred compensation plan	12,311	10,261
Non-interest bearing deposits	7,536,127	7,429,398
Savings, interest checking and money market deposits	11,091,200	11,430,789
Derivative Liabilities	5,979	13,339
Liabilities held in trust for deferred compensation plan	12,311	10,261
Fair Value Hierarchy, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Derivative Assets	0	0
Assets held in trust for deferred compensation plan	12,311	10,261
Derivative Liabilities	0	0
Liabilities held in trust for deferred compensation plan	12,311	10,261
Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	24,605	22,225
Derivative Assets	10,837	13,146
Assets held in trust for deferred compensation plan	0	0
Derivative Liabilities	5,850	13,177
Liabilities held in trust for deferred compensation plan	0	0
Fair Value Hierarchy, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Derivative Assets	813	420
Assets held in trust for deferred compensation plan	0	0
Derivative Liabilities	129	162
Liabilities held in trust for deferred compensation plan	0	0
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	951,519	945,871
Federal funds sold	32,630	15,470
Interest earning deposits with banks	105,422	272,275
Cash and due from banks	461,724	494,690
Assets held in trust for deferred compensation plan	12,311	10,261
Non-interest bearing deposits	7,536,127	7,429,398
Savings, interest checking and money market deposits	11,091,200	11,430,789
Federal Funds Purchased	350,910	52,840
Liabilities held in trust for deferred compensation plan	12,311	10,261
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value of Personal Real Estate Loans Held for Sale	17,337	14,456
Available for sale securities	8,140,915	8,686,650
Trading securities	24,605	22,225
Derivative Assets	10,837	13,146
Derivative Liabilities	5,850	13,177
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	16,853	16,682
Non-marketable	99,268	99,558
Securities purchased under agreements to resell	700,000	725,000
Derivative Assets	813	420
Time open and certificates of deposits	1,816,446	2,240,908
Securities Sold under Agreements to Repurchase	1,058,074	1,671,065
Other borrowings	102,553	102,049
Derivative Liabilities	129	162
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,834,037	4,776,365
Carrying (Reported) Amount, 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	921,609	791,236
Carrying (Reported) Amount, 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	2,700,174	2,643,374
Carrying (Reported) Amount, 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	2,029,302	2,010,397
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,113,438	1,990,801
Carrying (Reported) Amount, 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	391,308	413,634
Carrying (Reported) Amount, 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	752,379	776,465
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,245	10,464
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	951,519	945,871
Federal funds sold	32,630	15,470
Interest earning deposits with banks	105,422	272,275
Cash and due from banks	461,724	494,690
Assets held in trust for deferred compensation plan	12,311	10,261
Non-interest bearing deposits	7,536,127	7,429,398
Savings, interest checking and money market deposits	11,091,200	11,430,789
Federal Funds Purchased	350,910	52,840
Liabilities held in trust for deferred compensation plan	12,311	10,261
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value of Personal Real Estate Loans Held for Sale	17,337	14,456
Available for sale securities	8,140,915	8,686,650
Trading securities	24,605	22,225
Derivative Assets	10,837	13,146
Derivative Liabilities	5,850	13,177
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	16,853	16,682
Non-marketable	99,268	99,558
Securities purchased under agreements to resell	702,989	728,179
Derivative Assets	813	420
Time open and certificates of deposits	1,820,178	2,235,218
Securities Sold under Agreements to Repurchase	1,058,459	1,671,227
Other borrowings	103,012	104,298
Derivative Liabilities	129	162
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	4,848,169	4,787,469
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	933,862	800,426
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	2,712,002	2,658,093
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	2,034,374	2,005,227
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	2,088,302	1,974,784
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	391,419	414,499
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	767,344	794,856
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	$ 3,245	$ 10,464

Federal Home Loan Bank advances and other borrowings

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Interest Bearing Deposits With Federal Reserve Bank

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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

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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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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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