ADVANCES FROM THE FEDERAL HOME LOAN BANK (FHLB) - Additional Information (Detail) $ in Millions	Mar. 31, 2019 USD ($)
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Additional capacity on credit facility based on collateral pledged	$ 455.4
Federal Home Loan Bank Advances [Member]
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Letters of credit issued by the FHLB as pledges for public deposits in the Virgin Islands	$ 182.0

Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22 (b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(3)(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant