Loans and Leases (By Portfolio and Class) (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 47,823,875	$ 22,271,729
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	38,473,572	15,179,966
Commercial | Commercial non-mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	15,148,507	6,882,480
Commercial | Asset-based
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,803,719	1,067,248
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	12,742,888	5,463,321
Commercial | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	6,119,731	1,139,859
Commercial | Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,764,289	627,058
Commercial | Warehouse lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	894,438	0
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	9,350,303	7,091,763
Consumer | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	7,617,955	5,412,905
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,662,756	1,593,559
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 69,592	$ 85,299