INVESTMENT SECURITIES - Held to maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Mar. 31, 2021
INVESTMENT SECURITIES
Amortized Cost	$ 72,109	$ 39,574
Gross Unrealized Gains	9
Gross Unrealized Losses	(1,411)	(1,354)
Estimated Fair Value	70,707	38,220
Municipal securities
INVESTMENT SECURITIES
Amortized Cost	10,379	10,391
Gross Unrealized Gains	9
Gross Unrealized Losses	(340)	(509)
Estimated Fair Value	10,048	9,882
Agency securities
INVESTMENT SECURITIES
Amortized Cost	10,658	7,688
Gross Unrealized Losses	(213)	(220)
Estimated Fair Value	10,445	7,468
Real estate mortgage investment conduits
INVESTMENT SECURITIES
Amortized Cost	18,017	9,207
Gross Unrealized Losses	(264)	(141)
Estimated Fair Value	17,753	9,066
Residential mortgage-backed securities
INVESTMENT SECURITIES
Amortized Cost	20,806	6,175
Gross Unrealized Losses	(242)	(119)
Estimated Fair Value	20,564	6,056
Other mortgage-backed securities
INVESTMENT SECURITIES
Amortized Cost	12,249	6,113
Gross Unrealized Losses	(352)	(365)
Estimated Fair Value	$ 11,897	$ 5,748

Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919230-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 320
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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