Fair Value Measurements - Summary of Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 1,918,693	$ 1,176,652
Securities available for sale	4,419,413	4,541,925
Securities held to maturity	1,002	1,002
Other securities	349,380	322,048
Loans held for sale	68,176	56,879
Net loans	20,612,159	20,558,166
Derivative financial assets	5,283	5,550
Mortgage servicing rights	19,987	21,022
Deposits	22,284,586	22,303,166
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,918,693	1,176,652
Securities available for sale	4,419,413	4,541,925
Securities held to maturity	1,002	1,002
Other securities	349,380	322,048
Loans held for sale	68,176	56,879
Net loans	20,371,668	20,323,420
Derivative financial assets	5,283	5,550
Mortgage servicing rights	19,987	21,022
Deposits	22,284,586	22,303,186
Short-term borrowings	170,094	160,698
Long-term borrowings	2,788,103	2,197,656
Derivative financial liabilities	567	561
Carrying Amount [Member] \| Marketable Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities	7,792	7,629
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,918,693	1,176,652
Securities available for sale	4,419,413	4,541,925
Securities held to maturity	1,020	1,020
Other securities	331,911	305,946
Loans held for sale	68,176	56,879
Net loans	19,348,610	19,030,221
Derivative financial assets	5,283	5,550
Mortgage servicing rights	39,699	41,880
Deposits	22,229,264	22,249,061
Short-term borrowings	170,094	160,698
Long-term borrowings	2,750,992	2,161,108
Derivative financial liabilities	567	561
Fair Value [Member] \| Marketable Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities	7,792	7,629
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Securities available for sale	5,326	5,367
Securities held to maturity	0	0
Other securities	0	0
Loans held for sale	0	0
Net loans	0	0
Derivative financial assets	0	0
Mortgage servicing rights	0	0
Deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Derivative financial liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Marketable Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities	7,792	7,629
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,918,693	1,176,652
Securities available for sale	4,414,087	4,536,558
Securities held to maturity	0	0
Other securities	0	0
Loans held for sale	7,912	12,008
Net loans	0	0
Derivative financial assets	3,742	4,674
Mortgage servicing rights	0	0
Deposits	22,229,264	22,249,061
Short-term borrowings	170,094	160,698
Long-term borrowings	2,750,992	2,161,108
Derivative financial liabilities	84	0
Significant Other Observable Inputs (Level 2) [Member] \| Marketable Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities	0	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Securities available for sale	0	0
Securities held to maturity	1,020	1,020
Other securities	331,911	305,946
Loans held for sale	60,264	44,871
Net loans	19,348,610	19,030,221
Derivative financial assets	1,541	876
Mortgage servicing rights	39,699	41,880
Deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Derivative financial liabilities	483	561
Significant Unobservable Inputs (Level 3) [Member] \| Marketable Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities	$ 0	$ 0

The sum of cash and cash equivalents plus Federal Funds Sold. Cash and cash equivalents consist of short term, highly liquid investments that are readily convertible to known amounts of cash and are so near their maturity that they present negligible risk of changes in value due to changes in interest rates -- usually with an original maturity less than 90 days.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Amount of investments classified as other.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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