Revenue Recognition - Summary of Disaggregation of Revenue According to Revenue Stream and Business Segment (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	$ 18,798	$ 13,059	$ 61,050	$ 40,694
Noninterest income	203,298	158,743	591,681	462,906
Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	87,926	74,222	250,970	213,710
Trading and Investment Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	6,905	6,907	18,572	17,284
Noninterest income	7,026	7,118	19,107	18,041
Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	27	26	104	81
Noninterest income	29,150	20,089	85,472	63,107
Insurance Fees and Commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	307	282	674	832
Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	20,470	15,749	59,097	42,929
Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	(13,039)	(10,180)	(38,541)	(28,446)
Noninterest income	29,561	22,394	84,872	66,708
Investment Securities Gains (Losses), Net [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	(4,093)	2,623	28,810	10,127
Noninterest income	(4,093)	2,623	28,810	10,127
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	28,998	13,683	52,105	41,648
Noninterest income	32,951	16,266	62,679	47,452
Commercial Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	46,554	32,016	133,684	91,567
Commercial Banking [Member] \| Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	785		2,016
Commercial Banking [Member] \| Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	16,281	10,543	47,061	31,386
Commercial Banking [Member] \| Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	69	68	198	201
Commercial Banking [Member] \| Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	27,127	20,236	78,576	58,511
Commercial Banking [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	2,292	1,169	5,833	1,469
Institutional Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	103,700	89,497	298,828	258,806
Institutional Banking [Member] \| Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	67,201	59,843	192,026	170,394
Institutional Banking [Member] \| Trading and Investment Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	121	211	535	757
Institutional Banking [Member] \| Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	10,355	8,119	31,376	27,638
Institutional Banking [Member] \| Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	17,985	13,689	50,930	37,091
Institutional Banking [Member] \| Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	7,385	6,961	21,931	20,665
Institutional Banking [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	653	674	2,030	2,261
Personal Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	34,246	24,171	98,119	71,839
Personal Banking [Member] \| Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	19,940	14,379	56,928	43,316
Personal Banking [Member] \| Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	2,487	1,401	6,931	4,002
Personal Banking [Member] \| Insurance Fees and Commissions [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	307	282	674	832
Personal Banking [Member] \| Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	2,416	1,992	7,969	5,637
Personal Banking [Member] \| Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	8,088	5,377	22,906	15,978
Personal Banking [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	$ 1,008	$ 740	$ 2,711	$ 2,074

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The total amount of noninterest income which may be derived from: (1) fees and commissions; (2) premiums earned; (3) insurance policy charges; (4) the sale or disposal of assets; and (5) other sources not otherwise specified.

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