Loans and Leases (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Interest receivable	$ 90,000
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	8,220,000	$ 6,570,000
Advances from Federal Home Loan Banks		563,700
Federal Home Loan Bank Advances, Current Borrowing Capacity	7,430,000	6,010,000
Federal Reserve Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	3,150,000	2,980,000
Loans held for sale	76,300	67,900
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	1,400	900
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Purchase Discount Remaining	28,300	30,900
PCD Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Remaining discount	61,600	88,200
Federal Home Loan Bank of Atlanta
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Pledged as Collateral	10,310,000	9,410,000
Advances from Federal Home Loan Banks	787,700
Federal Reserve Bank
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Pledged as Collateral	$ 3,880,000	$ 3,680,000

Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Purchase Discount Remaining

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Amount of the collateral pledged in support of Federal Reserve Bank advances.

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Financing Receivable, Recorded Investment, Nonaccrual Status, Remaining Discount

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Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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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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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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