Estimated Fair Values (Estimated Fair Values For Certain Financial Assets And Financial Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 376,719	$ 327,440
Overnight investments	1,107,844	797,406
Investment securities available for sale	7,059,674	4,557,110
Investment securities held to maturity	30,996	2,184,653
Investment in marketable equity securities	82,333	92,599
Loans held for sale	67,900	45,500
Net loans and leases	28,656,355	25,299,564
Income earned not collected	123,154	109,903
Preferred stock	0	0
Deposits	34,431,236	30,672,460
Securities Sold under Agreements to Repurchase	442,956	543,936
Subordinated Debt	163,412	140,741
Other Borrowings	148,318	13,921
FDIC shared-loss payable	112,395	105,618	$ 101,342
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	376,719	327,440
Overnight investments	1,107,844	797,406
Investment securities available for sale	7,059,674	4,557,110
Investment securities held to maturity	30,996	2,184,653
Investment in marketable equity securities	82,333	92,599
Loans held for sale	67,869	45,505
Net loans and leases	28,656,355	25,299,564
Income earned not collected	123,154	109,903
Federal Home Loan Bank stock	43,039	25,304
Mortgage servicing assets	24,891	24,066
Deposits	34,431,236	30,672,460
Securities Sold under Agreements to Repurchase	442,956	543,936
Federal Home Loan Bank Advances	572,185	193,556
Subordinated Debt	163,412	140,741
Other Borrowings	148,318	13,921
FDIC shared-loss payable	112,395	105,618
Accrued interest payable	18,124	3,712
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	376,719	327,440
Overnight investments	1,107,844	797,406
Investment securities available for sale	7,059,674	4,557,110
Investment securities held to maturity	30,996	2,201,502
Investment in marketable equity securities	82,333	92,599
Loans held for sale	67,869	45,505
Net loans and leases	28,878,550	24,845,060
Income earned not collected	123,154	109,903
Federal Home Loan Bank stock	43,039	25,304
Mortgage servicing assets	26,927	27,435
Deposits	34,435,789	30,623,214
Securities Sold under Agreements to Repurchase	442,956	543,936
Federal Home Loan Bank Advances	577,362	195,374
Subordinated Debt	173,685	151,670
Other Borrowings	149,232	13,985
FDIC shared-loss payable	114,252	105,846
Accrued interest payable	$ 18,124	$ 3,712

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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Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions.

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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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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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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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