Loans and the Allowance for Credit Losses - Summary of Commercial Loans by Risk Grade (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	$ 18,828,626	$ 12,656,429
Commercial and Industrial [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	2,819,096	1,787,277
Commercial and Industrial [Member] | Pass [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	2,664,825	1,721,309
Commercial and Industrial [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	120,620	48,805
Commercial and Industrial [Member] | Classified - substandard [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	33,651	17,163
Commercial Portfolio Segment [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	13,419,306	9,113,958
Commercial Portfolio Segment [Member] | Pass [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	12,736,042	8,759,289
Commercial Portfolio Segment [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	531,415	242,000
Commercial Portfolio Segment [Member] | Classified - substandard [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	151,849	112,669
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	1,732,088	1,352,083
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Pass [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	1,657,871	1,347,374
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	59,225	3,873
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Classified - substandard [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	14,992	836
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	8,868,122	5,974,598
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Pass [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	8,413,346	5,690,606
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	351,570	189,322
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Classified - substandard [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	103,206	94,670
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	2,819,096	1,787,277
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Pass [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	2,664,825	1,721,309
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	120,620	48,805
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Classified - substandard [Member]
Summary of commercial loans by risk grade
Portfolio loans, net of unearned income	$ 33,651	$ 17,163