Credit Quality - Schedule of Age Analysis of its Past Due Loans, Segregated by Class of Loans and Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Loans, Past Due	$ 24,720,620	$ 21,680,498
Loans, Recorded Investment >90 Days & Accruing	4,974	16,940
30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	55,065	83,942
90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	101,466	73,400
Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	156,531	157,342
Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	24,564,089	21,523,156
Construction & Land Development [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	3,570,902	3,509,034
Loans, Recorded Investment >90 Days & Accruing	0	1,677
Construction & Land Development [Member] \| 30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	1,508	390
Construction & Land Development [Member] \| 90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	1,301	4,265
Construction & Land Development [Member] \| Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	2,809	4,655
Construction & Land Development [Member] \| Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	3,568,093	3,504,379
Commercial Real Estate [Member] \| Owner-Occupied [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	2,145,921	1,590,002
Loans, Recorded Investment >90 Days & Accruing	81	0
Commercial Real Estate [Member] \| Owner-Occupied [Member] \| 30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	4,754	3,767
Commercial Real Estate [Member] \| Owner-Occupied [Member] \| 90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	1,830	1,284
Commercial Real Estate [Member] \| Owner-Occupied [Member] \| Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	6,584	5,051
Commercial Real Estate [Member] \| Owner-Occupied [Member] \| Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	2,139,337	1,584,951
Commercial Real Estate [Member] \| Nonowner-Occupied [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	8,343,520	6,939,641
Loans, Recorded Investment >90 Days & Accruing	0	0
Commercial Real Estate [Member] \| Nonowner-Occupied [Member] \| 30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	7,598	11,931
Commercial Real Estate [Member] \| Nonowner-Occupied [Member] \| 90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	71,038	23,379
Commercial Real Estate [Member] \| Nonowner-Occupied [Member] \| Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	78,636	35,310
Commercial Real Estate [Member] \| Nonowner-Occupied [Member] \| Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	8,264,884	6,904,331
Other Commercial [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	3,784,833	3,351,362
Loans, Recorded Investment >90 Days & Accruing	591	431
Other Commercial [Member] \| 30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	2,490	5,594
Other Commercial [Member] \| 90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	6,569	19,019
Other Commercial [Member] \| Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	9,059	24,613
Other Commercial [Member] \| Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	3,775,774	3,326,749
Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	6,098,262	5,507,384
Loans, Recorded Investment >90 Days & Accruing	3,701	12,429
Residential Real Estate [Member] \| 30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	25,026	33,783
Residential Real Estate [Member] \| 90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	19,124	20,946
Residential Real Estate [Member] \| Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	44,150	54,729
Residential Real Estate [Member] \| Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	6,054,112	5,452,655
Consumer [Member] \| Bankcard [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	9,686	9,998
Loans, Recorded Investment >90 Days & Accruing	54	61
Consumer [Member] \| Bankcard [Member] \| 30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	28	63
Consumer [Member] \| Bankcard [Member] \| 90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	54	61
Consumer [Member] \| Bankcard [Member] \| Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	82	124
Consumer [Member] \| Bankcard [Member] \| Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	9,604	9,874
Consumer [Member] \| Other Consumer [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	767,496	773,077
Loans, Recorded Investment >90 Days & Accruing	547	2,342
Consumer [Member] \| Other Consumer [Member] \| 30-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	13,661	28,414
Consumer [Member] \| Other Consumer [Member] \| 90 Days or more Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	1,550	4,446
Consumer [Member] \| Other Consumer [Member] \| Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	15,211	32,860
Consumer [Member] \| Other Consumer [Member] \| Current & Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, Past Due	$ 752,285	$ 740,217