Loans and the Allowance for Credit Losses - Schedule of Recorded Investment in Loans by Category (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 11,873,167	$ 11,638,461
Loans held for sale	12,472	16,354
Total loans	11,885,639	11,654,815
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	1,683,172	1,670,659
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	6,754,933	6,565,448
Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	1,087,649	1,055,865
Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	5,667,284	5,509,583
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	2,469,357	2,438,574
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	224,732	229,561
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 740,973	$ 734,219