LOANS HELD FOR INVESTMENT - Loan Restructuring and Effect on Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loans and Leases Receivable Disclosure [Abstract]
Impact of adopting ASC 326	$ 116,900	$ 230,800
Provision (release) for credit losses	(61,720)	168,717	$ 40,225
Charge-offs		(47,900)	(81,400)
Accounting Standards Update 2016-13 [Member]
Loans and Leases Receivable Disclosure [Abstract]
Impact of adopting ASC 326		81,200
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Abstract]
Impact of adopting ASC 326	(61,600)
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans and Leases Receivable Disclosure [Abstract]
Provision (release) for credit losses	(1,408)	2,105	(1,496)
Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Loans and Leases Receivable Disclosure [Abstract]
Provision (release) for credit losses	(55,358)	81,125	(1,697)
Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Loans and Leases Receivable Disclosure [Abstract]
Provision (release) for credit losses	(8,549)	6,627	(13,696)
Entity Loan Modification Program [Member]
Financing Receivable, Troubled Debt Restructuring [Abstract]
Beginning Balance of TDRs	479,196	487,997	582,647
New TDRs loan splits	34,216	36,319	63,433
Increases to existing TDRs	94	6,009	1,840
Charge-offs post modification	(17,434)	(11,122)	(10,342)
Paid-off, partial payments and other	(52,724)	(37,992)	(136,709)
Ending balance of TDRs	414,738	479,196	$ 487,997
Entity Loan Modification Program [Member] \| Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable, Troubled Debt Restructuring [Abstract]
Beginning Balance of TDRs	3,423
Ending balance of TDRs	2,303	3,423
Entity Loan Modification Program [Member] \| Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Financing Receivable, Troubled Debt Restructuring [Abstract]
Beginning Balance of TDRs	64,438
Paid-off, partial payments and other	(92,400)
Ending balance of TDRs	68,833	64,438
Entity Loan Modification Program [Member] \| Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Financing Receivable, Troubled Debt Restructuring [Abstract]
Beginning Balance of TDRs	80,482
Ending balance of TDRs	$ 70,420	$ 80,482

Disbursements during the period on existing commitments of TDRs loans.

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Recorded investment in loans that were modified under troubled debt restructurings during the period.

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Repayments related to Trouble Debt Restructuring Loans.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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

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Amount of financing receivable modified as troubled debt restructuring.

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Reflects the amount of the write-down related to a troubled debt restructuring.

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Amount of expense related to estimated loss from loan and lease transactions.

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