Amount, after recoveries, of loans and leases that have been written-off.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of increase (decrease) in allowance for credit loss on financing receivable.

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of allowance for credit loss at acquisition date of financing receivable purchased with credit deterioration.

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Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

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ALLOWANCE FOR CREDIT LOSSES ON LOANS AND FINANCE LOSSES - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended			9 Months Ended
	Sep. 01, 2020	Jan. 01, 2020	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases			$ 384,718	$ 319,297	$ 165,575	$ 384,718	$ 165,575	$ 155,139	$ 172,011	$ 196,362
Increase (decrease) in ACL						229,600
Allowance established for acquired PCD loans	$ 28,744
Provision (release) for credit losses			48,078	36,400	7,398	158,531	31,752
Net charge-offs			11,400	9,900	13,800
Charge-offs			14,355		19,264	46,599	75,537
Recoveries			2,954		5,430	7,738	12,998
ACL for unfunded loan commitments and standby letters of credit			6,281	7,084	0	6,281	0	0	0	412
Provison (release) for credit losses on unfunded loan commitments and standby letters of credit			(803)		0	2,359	(412)
Santander [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Provison (release) for credit losses on unfunded loan commitments and standby letters of credit						1,300
Non-PCD Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Provision (release) for credit losses			37,500
Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases			42,909	38,310	17,618	42,909	17,618	15,198	21,644	32,546
Allowance established for acquired PCD loans	1,830
Provision (release) for credit losses			2,839		(5,465)	11,225	(11,068)
Charge-offs			150		387	323	7,056
Recoveries			80		1,826	248	3,196
Commercial Portfolio Segment [Member] \| V I \| Commercial And Industrial Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Recoveries							1,700
Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases			75,726	$ 49,435	44,848	75,726	44,848	$ 39,194	$ 46,373	$ 55,581
Allowance established for acquired PCD loans	$ 9,723
Provision (release) for credit losses			19,672		(808)	49,278	3,854
Charge-offs			3,157		813	3,303	14,901
Recoveries			53		$ 96	$ 140	$ 314
Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member] \| Florida region [Member] \| Nonperforming Financing Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Charge-offs			$ 3,100
ASC 326
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases		$ 236,304
ACL for unfunded loan commitments and standby letters of credit		3,922
ASC 326 \| Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases		29,929
ASC 326 \| Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases		19,888
ASC 326 \| Cumulative Effect Period Of Adoption Adjustment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases		81,165
Increase (decrease) in ACL		(434)
ACL for unfunded loan commitments and standby letters of credit		3,922
ASC 326 \| Cumulative Effect Period Of Adoption Adjustment [Member] \| Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases		14,731
ASC 326 \| Cumulative Effect Period Of Adoption Adjustment [Member] \| Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses on loans and finance leases		$ (19,306)