Loans and Leases - Schedule of Loans as Collateral (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Federal Home Loan Bank of Atlanta
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lendable collateral value of pledged non-PCD loans-FHLB	$ 8,847,178	$ 8,637,844
Less: Advances	648,671	652,675
Available borrowing capacity	8,198,507	7,985,169
Loans pledged as collateral	12,327,626	12,157,153
Federal Reserve Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lendable collateral value of pledged non-PCD loans-FRB	3,367,466	3,321,762
Less: Advances	0	0
Available borrowing capacity	3,367,466	3,321,762
Loans pledged as collateral	$ 4,181,520	$ 4,104,866

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

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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 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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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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