FEDERAL HOME LOAN BANK ADVANCES - Additional Information (Details) $ in Thousands	6 Months Ended
Sep. 30, 2023 USD ($)
FEDERAL HOME LOAN BANK ADVANCES
Loans pledged as collateral	$ 1,000,279
Assets pledged as collateral
FEDERAL HOME LOAN BANK ADVANCES
Percentage of total assets equal to bank credit line from FHLB	45.00%
Bank additional borrowing capacity from FHLB	$ 152,100
Assets pledged as collateral \| FHLB advances
FEDERAL HOME LOAN BANK ADVANCES
Loans pledged as collateral	$ 493,200

Amount of bank additional borrowing capacity from FHLB based on collateral values.

No definition available.

Name:	rvsb_FederalHomeLoanBankAdvancesAdditionalBorrowingCapacity
Namespace Prefix:	rvsb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of total assets which is equal to the bank credit line from FBHL.

+ References

No definition available.

+ Details

Name:	rvsb_FederalHomeLoanBankAdvancesCreditLinePercentageOfTotalAssets
Namespace Prefix:	rvsb_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_PledgedStatusAxis=us-gaap_AssetPledgedAsCollateralMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PledgingPurposeAxis=us-gaap_FederalHomeLoanBankAdvancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: