Transfers of Financial Assets - Carrying Amounts of Assets Pledged as Collateral, Borrowings and Other Transactions (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Carrying amounts of the assets pledged as collateral
Public deposits	$ 1,783,882	$ 1,913,369
Federal Home Loan Bank	2,269,584	2,380,042
Federal Reserve Bank	1,725,291	1,724,279
ACH transactions	112,800	115,038
Interest rate swaps	20,889	48,430
Total	5,912,446	6,181,158
Securities for reverse repurchase agreements	0	0
Extinguishment of debt
In-substance debt defeasance	0	0
FHLB fixed-rate advances
Carrying amounts of the assets pledged as collateral
Borrowing capacity	1,700,000	1,800,000
Federal Reserve Bank line of credit
Carrying amounts of the assets pledged as collateral
Borrowing capacity	$ 1,300,000	$ 1,100,000

Amount of debt extinguished by in-substance defeasance.

No definition available.

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- Definition

Sum of the carrying amounts as of the date of the latest financial statement presented of financial assets which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

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- Definition

The carrying amount as of the date of the latest financial statement presented of financial assets which are owned but transferred to serve as collateral for Automated Clearing House (ACH) obligations, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

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- Definition

The carrying amount as of the date of the latest financial statement presented of financial assets which are owned but transferred to serve as collateral for derivative contracts, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

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- Definition

The carrying amount, as of the date of the latest financial statement presented, of loans receivable and securities which are owned but transferred to serve as collateral for the payment of FHLB debt obligations, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

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- Definition

The carrying amount, as of the date of the latest financial statement presented, of loans receivable and securities which are owned but transferred to serve as collateral for the payment of Federal Reserve Bank debt obligations, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

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- Definition

The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for public deposits, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

+ References

No definition available.

+ Details

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- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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- References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

The carrying value of securities purchased to be resold in reverse repurchase transactions as of the balance sheet date.

+ References

No definition available.

+ Details

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- Details

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- Details

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