LOANS - Average Recorded Investment of Impaired Loans by Class of Loan (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Impaired [Line Items]
With no allowance recorded:	$ 27,856	$ 2,889
With an allowance recorded:	369	3,353
Total average recorded investment	28,225	6,242
Construction and land development
Financing Receivable, Impaired [Line Items]
With no allowance recorded:	10	768
With an allowance recorded:	0	183
Commercial real estate: \| Nonfarm, nonresidential
Financing Receivable, Impaired [Line Items]
With no allowance recorded:	4,584	51
With an allowance recorded:	156	0
Residential real estate:
Financing Receivable, Impaired [Line Items]
With an allowance recorded:	213	0
Residential real estate: \| Closed-end 1-4 family
Financing Receivable, Impaired [Line Items]
With no allowance recorded:	1,260	806
Residential real estate: \| Other
Financing Receivable, Impaired [Line Items]
With no allowance recorded:	2,840	1,264
Commercial and industrial
Financing Receivable, Impaired [Line Items]
With no allowance recorded:	19,162	0
With an allowance recorded:	$ 0	$ 3,170

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

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