LOANS HELD FOR INVESTMENT - Reconciliation of the Par Value of Loans Acquired in the Santander Acquisition with te Purchase Price (Detail) - USD ($) $ in Thousands	Sep. 01, 2020	Jan. 01, 2020
Purchase price of loans at acquisition (initial fair value)	$ 752,826
Allowance established for acquired PCD loans	28,744	$ 28,700
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)	4,479
Par value of acquired loans at acquisition	786,049
Residential Portfolio Segment [Member]
Purchase price of loans at acquisition (initial fair value)	322,345
Allowance established for acquired PCD loans	12,739
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)	3,075
Par value of acquired loans at acquisition	338,159
Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Purchase price of loans at acquisition (initial fair value)	194,572
Allowance established for acquired PCD loans	1,830
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)	(95)
Par value of acquired loans at acquisition	196,307
Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Purchase price of loans at acquisition (initial fair value)	180,950
Allowance established for acquired PCD loans	9,723
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)	2,783
Par value of acquired loans at acquisition	193,456
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Purchase price of loans at acquisition (initial fair value)	0
Allowance established for acquired PCD loans	0
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)	0
Par value of acquired loans at acquisition	0
Consumer Portfolio Segment [Member]
Purchase price of loans at acquisition (initial fair value)	54,959
Allowance established for acquired PCD loans	4,452
Financing Receivable, Purchased with Credit Deterioration, Discount (Premium)	(1,284)
Par value of acquired loans at acquisition	$ 58,127

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 19
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919265-210447

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Amount at par value of financing receivable purchased with credit deterioration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 19
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919265-210447

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Amount at purchase price of financing receivable purchased with credit deterioration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 19
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919265-210447

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Amount of discount (premium) attributable to other factors on financing receivable purchased with credit deterioration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 19
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919265-210447

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