Fair Value Of Financial Instruments (Schedule Of Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value of Personal Real Estate Loans Held for Sale	$ 7,400
Available for sale securities	9,671,975	$ 9,649,203
Trading securities	20,200	22,225
Non-marketable	101,688	99,558
Securities purchased under agreements to resell	725,000	725,000
Cash and due from banks	416,161	494,690
Derivative Assets	9,885	13,566
Assets held in trust for deferred compensation plan	11,583	10,261
Non-interest bearing deposits	7,237,815	7,429,398
Savings, interest checking and money market deposits	11,439,078	11,430,789
Derivative Liabilities	7,398	13,339
Liabilities held in trust for deferred compensation plan	11,583	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	11,583	10,261
Derivative Liabilities	0	0
Liabilities held in trust for deferred compensation plan	11,583	10,261
Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	20,200	22,225
Derivative Assets	8,925	13,146
Assets held in trust for deferred compensation plan	0	0
Derivative Liabilities	7,260	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	960	420
Assets held in trust for deferred compensation plan	0	0
Derivative Liabilities	138	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	939,499	945,871
Federal funds sold	2,205	15,470
Interest earning deposits with banks	120,234	272,275
Cash and due from banks	416,161	494,690
Assets held in trust for deferred compensation plan	11,583	10,261
Non-interest bearing deposits	7,237,815	7,429,398
Savings, interest checking and money market deposits	11,439,078	11,430,789
Federal Funds Purchased	340,195	52,840
Liabilities held in trust for deferred compensation plan	11,583	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	15,559	14,456
Available for sale securities	8,715,393	8,686,650
Trading securities	20,200	22,225
Derivative Assets	8,925	13,146
Derivative Liabilities	7,260	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	17,083	16,682
Non-marketable	101,688	99,558
Securities purchased under agreements to resell	725,000	725,000
Derivative Assets	960	420
Time open and certificates of deposits	2,414,960	2,240,908
Securities Sold under Agreements to Repurchase	980,954	1,671,065
Other borrowings	101,975	102,049
Derivative Liabilities	138	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	4,888,011	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	846,904	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	2,710,595	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	2,013,437	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	1,975,521	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	396,542	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	736,766	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	4,733	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	939,499	945,871
Federal funds sold	2,205	15,470
Interest earning deposits with banks	120,234	272,275
Cash and due from banks	416,161	494,690
Assets held in trust for deferred compensation plan	11,583	10,261
Non-interest bearing deposits	7,237,815	7,429,398
Savings, interest checking and money market deposits	11,439,078	11,430,789
Federal Funds Purchased	340,195	52,840
Liabilities held in trust for deferred compensation plan	11,583	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	15,559	14,456
Available for sale securities	8,715,393	8,686,650
Trading securities	20,200	22,225
Derivative Assets	8,925	13,146
Derivative Liabilities	7,260	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	17,083	16,682
Non-marketable	101,688	99,558
Securities purchased under agreements to resell	728,705	728,179
Derivative Assets	960	420
Time open and certificates of deposits	2,406,892	2,235,218
Securities Sold under Agreements to Repurchase	981,155	1,671,227
Other borrowings	103,564	104,298
Derivative Liabilities	138	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	4,897,223	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	856,027	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	2,723,734	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	2,006,535	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	1,957,407	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	397,307	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	754,362	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	$ 4,733	$ 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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Non-Marketable investments include Federal Home Loan Bank stock, Federal Reserve Bank stock, and private equity investments.

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

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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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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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The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

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Amount, after the effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes purchases of participations in pools of securities that are subject to a resale agreement, assets not subject to a master netting arrangement and not elected to be offset.

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