Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities to Borrowers Experiencing Financial Difficulty on Financing Receivables (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2023	Jun. 30, 2023
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 347,821	$ 640,328
Guaranteed by Government-Related Entities [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 25,000	$ 48,000

[1] Includes approximately $25 million and $48 million, respectively, of loans guaranteed by government-related entities (predominantly first lien residential mortgage loans) for the three-month and six-month periods ended June 30, 2023.