Loans and Allowance for Credit Losses - Credit Risk Profile Based on Payment Activity (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity	$ 16,103,651	$ 13,431,722	$ 12,178,150
Leases Portfolio [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		1,978	$ 5,248
Originated and Non-PCI Loans [Member] | Leases Portfolio [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		1,978
Originated and Non-PCI Loans [Member] | Performing [Member] | Leases Portfolio [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		1,978
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		182,238
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		182,214
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		24
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		933,276
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		926,312
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		6,964
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		478,151
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		468,228
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		9,923
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		226,742
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		225,939
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		803
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		133,474
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		132,414
Commercial Credit Card [Member] | Originated and Non-PCI Loans [Member] | Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile Based on Payment Activity		$ 1,060