Fair Value of Assets and Liabilities - Summary Of The Balances Of Assets And Liabilities Measured At Fair Value On A Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets
Securities available for sale	$ 4,520,293	$ 6,690,778
Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	2,891,064	4,111,908
Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	1,140,160	1,348,954
U.S. Agency bonds
Assets
Securities available for sale	210,070	952,482
U.S. Treasury securities
Assets
Securities available for sale	93,082	93,057
Other debt securities
Assets
Securities available for sale	100	1,285
Fair Value, Recurring
Assets
Rabbi trust investments	82,638	76,286
Loans held for sale	2,835	4,543
Risk participation agreements	96	78
Matched customer book	118	198
Foreign currency loan		2
Mortgage derivatives	15	62
Total	4,628,215	6,795,530
Liabilities
Risk participation agreements	119	130
Matched customer book	105	205
Foreign currency loan	243	93
Mortgage derivatives	42	58
Total	78,998	81,480
Fair Value, Recurring \| Designated as Hedging Instrument
Assets
Interest rate swap contracts	1,378	16
Liabilities
Interest rate swap contracts	25	2,417
Fair Value, Recurring \| Not Designated as Hedging Instrument
Assets
Interest rate swap contracts	20,842	23,567
Liabilities
Interest rate swap contracts	78,464	78,577
Fair Value, Recurring \| Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	2,891,064	4,111,908
Fair Value, Recurring \| Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	1,140,160	1,348,954
Fair Value, Recurring \| U.S. Agency bonds
Assets
Securities available for sale	210,070	952,482
Fair Value, Recurring \| U.S. Treasury securities
Assets
Securities available for sale	93,082	93,057
Fair Value, Recurring \| State and municipal bonds and obligations
Assets
Securities available for sale	185,817	183,092
Fair Value, Recurring \| Other debt securities
Assets
Securities available for sale	100	1,285
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Rabbi trust investments	76,253	69,257
Loans held for sale	0	0
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan		0
Mortgage derivatives	0	0
Total	169,335	162,314
Liabilities
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan	0	0
Mortgage derivatives	0	0
Total	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Designated as Hedging Instrument
Assets
Interest rate swap contracts	0	0
Liabilities
Interest rate swap contracts	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Not Designated as Hedging Instrument
Assets
Interest rate swap contracts	0	0
Liabilities
Interest rate swap contracts	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. Agency bonds
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. Treasury securities
Assets
Securities available for sale	93,082	93,057
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| State and municipal bonds and obligations
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other debt securities
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2)
Assets
Rabbi trust investments	6,385	7,029
Loans held for sale	2,835	4,543
Risk participation agreements	96	78
Matched customer book	118	198
Foreign currency loan		2
Mortgage derivatives	15	62
Total	4,458,880	6,633,216
Liabilities
Risk participation agreements	119	130
Matched customer book	105	205
Foreign currency loan	243	93
Mortgage derivatives	42	58
Total	78,998	81,480
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Designated as Hedging Instrument
Assets
Interest rate swap contracts	1,378	16
Liabilities
Interest rate swap contracts	25	2,417
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Not Designated as Hedging Instrument
Assets
Interest rate swap contracts	20,842	23,567
Liabilities
Interest rate swap contracts	78,464	78,577
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	2,891,064	4,111,908
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	1,140,160	1,348,954
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| U.S. Agency bonds
Assets
Securities available for sale	210,070	952,482
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| U.S. Treasury securities
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| State and municipal bonds and obligations
Assets
Securities available for sale	185,817	183,092
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Other debt securities
Assets
Securities available for sale	100	1,285
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3)
Assets
Rabbi trust investments	0	0
Loans held for sale	0	0
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan		0
Mortgage derivatives	0	0
Total	0	0
Liabilities
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan	0	0
Mortgage derivatives	0	0
Total	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Designated as Hedging Instrument
Assets
Interest rate swap contracts	0	0
Liabilities
Interest rate swap contracts	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Not Designated as Hedging Instrument
Assets
Interest rate swap contracts	0	0
Liabilities
Interest rate swap contracts	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| U.S. Agency bonds
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| U.S. Treasury securities
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| State and municipal bonds and obligations
Assets
Securities available for sale	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Other debt securities
Assets
Securities available for sale	$ 0	$ 0

Foreign Currency Loan, Asset

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Interest rate derivative liabilities one.

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Mortgage Derivatives, Asset

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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The total amount of cash and securities held by third party trustees pursuant to terms of debt instruments or other agreements as of the date of each statement of financial position presented, which can be used by the trustee only to pay the noncurrent portion of specified obligations.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
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Fair value as of the balance sheet date of all interest rate derivative assets designated as cash flow hedging instruments.

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Fair value of financial and nonfinancial obligations.

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