Loans and Leases (By Portfolio and Class) (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 43,536,485	$ 22,271,729
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	34,971,086	15,179,966
Commercial | Commercial non-mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,105,173	6,882,480
Commercial | Asset-based
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,807,545	1,067,248
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	11,957,747	5,463,321
Commercial | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,627,200	1,139,859
Commercial | Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,909,284	627,058
Commercial | Warehouse lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	564,137	0
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	8,565,399	7,091,763
Consumer | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	6,798,199	5,412,905
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,679,443	1,593,559
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 87,757	$ 85,299