Federal Home Loan Bank Advances and Long-Term Debt (FHLB Advances and LTD) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Federal Home Loan Bank (“FHLB”) advances	$ 652,612	$ 745,915
Available borrowing capacity from FHLB advances	$ 6,330,000	$ 6,830,000
FHLB Advances
Debt Instrument [Line Items]
Weighted-average rate (as a percent)	1.77%	2.19%
Parent Company
Debt Instrument [Line Items]
Junior Subordinated Notes	$ 147,376	$ 147,101
Weighted-average rate (as a percent)	2.26%	3.98%
Bank \| FHLB - Fixed
Debt Instrument [Line Items]
Federal Home Loan Bank (“FHLB”) advances	$ 405,000	$ 400,000
Bank \| FHLB - Floating
Debt Instrument [Line Items]
Federal Home Loan Bank (“FHLB”) advances	$ 247,612	$ 345,915
Minimum \| Parent Company \| Subordinated Debt
Debt Instrument [Line Items]
Variable interest rate	1.57%
Minimum \| Bank \| FHLB - Fixed
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	0.00%
Minimum \| Bank \| FHLB - Floating
Debt Instrument [Line Items]
Variable interest rate	0.60%
Maximum \| Parent Company \| Subordinated Debt
Debt Instrument [Line Items]
Variable interest rate	2.12%
Maximum \| Bank \| FHLB - Fixed
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	2.34%
Maximum \| Bank \| FHLB - Floating
Debt Instrument [Line Items]
Variable interest rate	0.63%

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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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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