Estimated Fair Values (Estimated Fair Values For Certain Financial Assets And Financial Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 327,440	$ 336,150
Overnight investments	797,406	1,387,927
Investment securities available for sale	4,557,110	7,180,180
Investment securities held to maturity	2,184,653	76
Investment in marketable equity securities	92,599	0
Net loans and leases	25,299,564	23,374,932
Income earned not collected	109,903	95,249
Preferred stock	0	0
Deposits	30,672,460	29,266,275
Short-term borrowings	572,287	693,807
Long-term obligations	319,867	870,240
FDIC shared-loss payable	105,618	101,342	$ 97,008
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	327,440	336,150
Overnight investments	797,406	1,387,927
Investment securities available for sale	4,557,110	7,180,180
Investment securities held to maturity	2,184,653	76
Investment in marketable equity securities	92,599	0
Loans held for sale	45,505	51,179
Net loans and leases	25,299,564	23,374,932
Income earned not collected	109,903	95,249
Federal Home Loan Bank stock	25,304	52,685
Mortgage servicing assets	24,066	21,945
Deposits	30,672,460	29,266,275
Short-term borrowings	572,287	693,807
Long-term obligations	319,867	870,240
FDIC shared-loss payable	105,618	101,342
Accrued interest payable	3,712	3,952
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	327,440	336,150
Overnight investments	797,406	1,387,927
Investment securities available for sale	4,557,110	7,180,180
Investment securities held to maturity	2,201,502	81
Investment in marketable equity securities	92,599	0
Loans held for sale	45,505	51,179
Net loans and leases	24,845,060	22,257,803
Income earned not collected	109,903	95,249
Federal Home Loan Bank stock	25,304	52,685
Mortgage servicing assets	29,532	26,170
Deposits	30,623,214	29,230,768
Short-term borrowings	572,287	693,807
Long-term obligations	332,678	852,112
FDIC shared-loss payable	105,846	102,684
Accrued interest payable	$ 3,712	$ 3,952

Payable to FDIC for Loss Share Agreements

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For an unclassified balance sheet, the amount of fees and other revenue, excluding investment income receivable, earned but not yet received, which were recognized in conformity with revenue recognition criteria based on estimates or specific contractual terms.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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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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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of interest payable on debt, including, but not limited to, trade payables.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of short-term investments classified as other.

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Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.

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Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

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