Loans and Allowance for Loan Losses - Credit Risk Profile by Risk Rating - Originated and Non-PCI Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	$ 13,431,722	$ 12,178,150	$ 11,280,513
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	5,842,002	5,228,402
Commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	5,842,002	5,228,402
Asset-based [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	292,231	380,738
Asset-based [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	292,231	380,738
Factoring [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	170,560	261,591
Factoring [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	170,560	261,591
Real estate - construction [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	842,346	792,565
Real estate - commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	4,328,724	3,714,280
Real estate - commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	4,328,724	3,714,280
Non-watch list [Member] | Commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	5,380,205	4,788,234
Non-watch list [Member] | Asset-based [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	230,526	296,719
Non-watch list [Member] | Factoring [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	127,310	260,727
Non-watch list [Member] | Real estate - construction [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	837,836	792,256
Non-watch list [Member] | Real estate - commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	4,078,673	3,551,537
Watch [Member] | Commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	257,040	192,653
Watch [Member] | Real estate - construction [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	175	204
Watch [Member] | Real estate - commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	110,530	64,998
Special Mention [Member] | Commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	91,020	55,927
Special Mention [Member] | Asset-based [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	34,640	84,019
Special Mention [Member] | Factoring [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	1,376	864
Special Mention [Member] | Real estate - construction [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	307
Special Mention [Member] | Real estate - commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	28,020	32,826
Substandard [Member] | Commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	113,737	191,588
Substandard [Member] | Asset-based [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	27,065
Substandard [Member] | Factoring [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	41,874
Substandard [Member] | Real estate - construction [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	4,028	105
Substandard [Member] | Real estate - commercial [Member] | Originated and Non-PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit Risk Profile by Risk Rating	$ 111,501	$ 64,919