Borrowed Funds - Schedule of Short-Term Borrowings (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total short-term borrowings	$ 783,346	$ 1,147,958
Short-term borrowings
Debt Instrument [Line Items]
FHLB advances	600,000	1,000,000
Securities sold under agreements to repurchase	183,346	147,958
Total short-term borrowings	$ 783,346	$ 1,147,958

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Amount of advance from Federal Home Loan Bank (FHLBank) maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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