Loans and the Allowance for Credit Losses - Schedule of Recorded Investment in Loans by Category (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 11,315,873	$ 10,702,728
Loans held for sale	17,677	8,249
Total loans	11,333,550	10,710,977
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	1,587,611	1,579,395
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	6,387,183	6,061,344
Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	870,066	943,887
Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	5,517,117	5,117,457
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	2,392,531	2,140,584
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	233,362	226,340
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 715,186	$ 695,065