Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Percentage of periodic changes in fair value qualifies for hedge accounting treatment	100.00%
Interest Income
Derivative [Line Items]
Reclassified interest income (expense)	$ 4,500
Interest Expense
Derivative [Line Items]
Reclassified interest income (expense)	500
Interest rate swaps on borrowings \| Cash flow hedges \| Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	150,000	$ 325,000
Interest rate swaps on borrowings \| Fair value hedges \| Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	379,000	379,000
Interest rate collars and floors on loan pools \| Cash flow hedges \| Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	400,000	400,000
Interest rate swaps on investment securities \| Fair value hedges \| Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	884,957	347,516
Interest rate lock commitments \| Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	237,439	224,719
Forward mortgage loan contracts \| Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	273,710	261,027
Counterparty interest rate swaps \| Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	2,098,087	2,008,149
Customer interest rate swaps \| Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	$ 2,098,087	$ 2,008,149

Percentage of periodic changes in fair value qualifies for hedge accounting.

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- Definition

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.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

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- Definition

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994

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