Cash Distribution from Equity Method Investment, Gross

No definition available.

Name:	brn_CashDistributionFromEquityMethodInvestmentGross
Namespace Prefix:	brn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Cash Distribution from Equity Method Investment, Net

+ References

No definition available.

+ Details

Name:	brn_CashDistributionFromEquityMethodInvestmentNet
Namespace Prefix:	brn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Cumulative Cash Distributions from Kukio Resort Land Development Partnerships, Partial Payment Preferred Return

+ References

No definition available.

+ Details

Name:	brn_CumulativeCashDistributionsFromKukioResortLandDevelopmentPartnershipsPartialPaymentPreferredReturn
Namespace Prefix:	brn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Cumulative Cash Distributions from Kukio Resort Land Development Partnerships, Preferred Return Made to Date

+ References

No definition available.

+ Details

Name:	brn_CumulativeCashDistributionsFromKukioResortLandDevelopmentPartnershipsPreferredReturnMadeToDate
Namespace Prefix:	brn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cumulative cash distributions from Kukio Resort Land Development Partnerships (to all partners), made to date.

+ References

No definition available.

+ Details

Name:	brn_CumulativeCashDistributionsfromKukioResortLandDevelopmentPartnershipsMadetoDate
Namespace Prefix:	brn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cumulative cash distributions from Kukio Resort Land Development Partnerships, threshold, after which BHP receives a preferred return from KKM, up to $1M.

+ References

No definition available.

+ Details

Name:	brn_CumulativeCashDistributionsfromKukioResortLandDevelopmentPartnershipsThreshold
Namespace Prefix:	brn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Increment II Lot size

+ References

No definition available.

+ Details

Name:	brn_IncrementIILotsize
Namespace Prefix:	brn_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of large remaining residential lots to be sold by the Land Development Partnerships

+ References

No definition available.

+ Details

Name:	brn_NumberOfLargeResidentialLotsRemainingToBeSold
Namespace Prefix:	brn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of limited liability limited partnerships formed through a wholly-owed subsidiary.

+ References

No definition available.

+ Details

Name:	brn_NumberOfLimitedLiabilityLimitedPartnershipsFormed
Namespace Prefix:	brn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Original Size Residential Lots Remaining to be Sold

+ References

No definition available.

+ Details

Name:	brn_NumberOfOriginalSizeResidentialLotsRemainingToBeSold
Namespace Prefix:	brn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of single-family lots sold.

+ References

No definition available.

+ Details

Name:	brn_NumberOfSingleFamilyLotsSold
Namespace Prefix:	brn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of lots developed

+ References

No definition available.

+ Details

Name:	brn_NumberofLotsDeveloped
Namespace Prefix:	brn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of remaining residential lots to be sold by the Land Development Partnerships

+ References

No definition available.

+ Details

Name:	brn_NumberofResidentialLotsRemainingtobeSold
Namespace Prefix:	brn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

+ References

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 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of income (loss) for proportionate share of equity method investee's income (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(12))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(10))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(13)(f))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570

+ Details

Name:	us-gaap_IncomeLossFromEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_InvestmentHoldingsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

+ References

+ Details

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

- Details

Name:	us-gaap_InvestmentTypeAxis=brn_LandDevelopmentPartnershipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KDKukioResortsLLLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KDKaupulehuLLLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KDManiniowaliLLLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_IndirectlyAcquiredInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KDAcquisitionLLLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KDKona2013LLLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KKMMakaiLLLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=brn_KDKaupulehuLLLPIncrementIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=brn_KDKaupulehuLLLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KDAcquisitionIILPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=brn_KaupulehuDevelopmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=brn_KDKaupulehuLLLPIncrementIIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=brn_ReplayKaupulehuDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=brn_BarnwellIndustriesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_NoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

INVESTMENTS - INVESTMENT IN KUKIO RESORT LAND DEVELOPMENT PARTNERSHIP (Details) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Nov. 27, 2013 USD ($) partnership	Jun. 30, 2022 USD ($) lot	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) lot	Jun. 30, 2021 USD ($)	Sep. 30, 2017 a	Sep. 30, 2016	Mar. 31, 2022 lot	Mar. 07, 2019
Investment Holdings [Line Items]
Equity in income of affiliates		$ 433	$ 3,348	$ 3,400	$ 5,026
Investment in land development partnerships
Investment Holdings [Line Items]
Number of limited liability limited partnerships formed \| partnership	2
Cumulative cash distributions from Kukio Resort Land Development Partnerships made to date				45,000
Cumulative cash distributions from Kukio Resort Land Development Partnerships, partial payment preferred return					459
Cumulative cash distributions from Kukio Resort land development Partnerships, preferred return				656
Cash distribution from equity method investment, gross				3,400
Cash distribution from equity method investment, net				3,028	5,328
Equity in income of affiliates		$ 433	3,348	$ 3,400	5,026
Investment in Kukio Resort Land Development Partnerships			$ 0		0
K D Kukio Resorts LLLP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired	19.60%
KD Kaupulehu, LLLP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired	19.60%
KD Maniniowali L L L P \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired	19.60%
Indirectly Acquired Interest \| Investment in land development partnerships
Investment Holdings [Line Items]
Aggregate cost	$ 5,140
KD Acquisition, LLLP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired		19.60%		19.60%
KD Kona 2013 LLLP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired	75.00%
KKM Makai LLLP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired	34.45%
KD Kaupulehu LLLP Increment I \| Investment in land development partnerships
Investment Holdings [Line Items]
Number of residential lots remaining to be sold \| lot		2		2				2
Number of large residential lots remaining to be sold \| lot		1		1
Number of original size residential lots remaining to be sold \| lot		1		1
KD Kaupulehu, LLLP \| KD Acquisition II, LP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired									55.00%
Kaupulehu Developments \| KD Kaupulehu LLLP Increment II
Investment Holdings [Line Items]
Number of lots developed						2
Number of single family lots sold						1	1
Replay \| KD Acquisition II, LP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired									45.00%
Barnwell Industries Inc \| KD Acquisition II, LP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired		10.80%		10.80%
Non-controlling Interests \| Investment in land development partnerships
Investment Holdings [Line Items]
Cash distribution from equity method investment, net				$ 372	$ 599
Minimum \| Investment in land development partnerships
Investment Holdings [Line Items]
Cumulative cash distributions from Kukio Resort Land Development Partnerships, threshold	$ 45,000
Minimum \| Kaupulehu Developments \| KD Kaupulehu LLLP Increment II
Investment Holdings [Line Items]
Increment II lot size \| a						2
Maximum \| Kaupulehu Developments \| KD Kaupulehu LLLP Increment II
Investment Holdings [Line Items]
Increment II lot size \| a						3