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ALLOWANCE FOR CREDIT LOSSES ON LOANS AND FINANCE LEASES - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Sep. 01, 2020	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable Allowance For Credit Losses [Line Items]
Financing Receivable Allowance For Credit Losses			$ 260,464	$ 269,030	$ 385,887	$ 155,139
Increase (decrease) in ACL			(8,500)
Provision for credit losses - (benefit) expense			25,679	(61,720)	168,717
Net charge-offs			34,200
Increase (decrease) in net charge-offs			(20,900)
Recoveries			23,085	25,573	16,662
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)			2,736	(3,568)	1,183
Off-Balance Sheet, Credit Loss, Liability			4,273	1,537	5,105	0
Charge-offs			57,330	80,710	64,540
Residential Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Financing Receivable Allowance For Credit Losses			62,760	74,837	120,311	44,806
Increase (decrease) in ACL			(12,000)
Provision for credit losses - (benefit) expense			(8,734)	(16,957)	22,427
Increase (decrease) in net charge-offs			(25,200)
Recoveries			3,547	4,777	1,519
Charge-offs			6,890	33,294	11,017
Residential Portfolio Segment [Member] \| Nonaccrual loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Charge-offs		$ 23,100
Commercial Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Increase (decrease) in ACL			(20,800)
Increase (decrease) in net charge-offs			1,500
Amount of reserve released associated with classified loans			4,800
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Financing Receivable Allowance For Credit Losses			2,308	4,048	5,380	2,370
Provision for credit losses - (benefit) expense			(2,342)	(1,408)	2,105
Recoveries			725	163	184
Charge-offs			123	87	76
Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Financing Receivable Allowance For Credit Losses			35,064	52,771	109,342	39,194
Provision for credit losses - (benefit) expense			(18,994)	(55,358)	81,125
Recoveries			1,372	281	1,936
Charge-offs			85	1,494	3,330
Consumer Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Financing Receivable Allowance For Credit Losses			127,426	103,090	112,910	$ 53,571
Increase (decrease) in ACL			24,300
Provision for credit losses - (benefit) expense			57,519	20,552	56,433
Increase (decrease) in net charge-offs			2,800
Recoveries			14,982	13,576	9,831
Charge-offs			$ 48,165	$ 43,948	$ 46,483
Non-PCD \| Santander [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Provision for credit losses - (benefit) expense	$ 37,500
Non-PCD \| Santander [Member] \| Residential Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Provision for credit losses - (benefit) expense	13,500
Non-PCD \| Santander [Member] \| Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Provision for credit losses - (benefit) expense	9,200
Non-PCD \| Santander [Member] \| Consumer Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Provision for credit losses - (benefit) expense	$ 10,200