Estimated Fair Values (Estimated Fair Values For Certain Financial Assets And Financial Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 362,048	$ 376,719
Overnight investments	4,347,336	1,107,844
Investment securities available for sale	7,014,243	7,059,674
Investment securities held to maturity	2,816,982	30,996
Investment in marketable equity securities	91,680	82,333
Loans held for sale	124,800	67,900
Net loans and leases	32,567,661	28,656,355
Income earned not collected	145,694	123,154
Deposits	43,431,609	34,431,236
Time Deposits	2,889,013	3,837,609
Securities Sold under Agreements to Repurchase	641,487	442,956
Subordinated Debt	504,518	163,412
Other Borrowings	88,470	148,318
FDIC shared-loss payable	15,601	112,395	$ 105,618
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	362,048	376,719
Overnight investments	4,347,336	1,107,844
Investment securities available for sale	7,014,243	7,059,674
Investment securities held to maturity	2,816,982	30,996
Investment in marketable equity securities	91,680	82,333
Loans held for sale	124,837	67,869
Net loans and leases	32,567,661	28,656,355
Income earned not collected	145,694	123,154
Federal Home Loan Bank stock	45,392	43,039
Mortgage servicing assets	19,628	24,891
Deposits	40,542,596	30,593,627
Time Deposits	2,889,013	3,837,609
Securities Sold under Agreements to Repurchase	641,487	442,956
Federal Home Loan Bank Advances	655,175	572,185
Subordinated Debt	504,518	163,412
Other Borrowings	88,470	148,318
FDIC shared-loss payable	15,601	112,395
Accrued interest payable	9,414	18,124
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	362,048	376,719
Overnight investments	4,347,336	1,107,844
Investment securities available for sale	7,014,243	7,059,674
Investment securities held to maturity	2,838,499	30,996
Investment in marketable equity securities	91,680	82,333
Loans held for sale	124,837	67,869
Net loans and leases	33,298,166	28,878,550
Income earned not collected	145,694	123,154
Federal Home Loan Bank stock	45,392	43,039
Mortgage servicing assets	20,283	26,927
Deposits	40,542,596	30,593,627
Time Deposits	2,905,577	3,842,162
Securities Sold under Agreements to Repurchase	641,487	442,956
Federal Home Loan Bank Advances	677,579	577,362
Subordinated Debt	525,610	173,685
Other Borrowings	89,263	149,232
FDIC shared-loss payable	15,843	114,252
Accrued interest payable	$ 9,414	$ 18,124

Payable to FDIC for Loss Share Agreements

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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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