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 In Excess of Our Investment Balance

+ References

No definition available.

+ Details

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

- 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 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 https://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 https://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 https://asc.fasb.org/extlink&oid=126953954&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 https://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 https://asc.fasb.org/extlink&oid=126954810&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 https://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 https://asc.fasb.org/extlink&oid=126901519&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 https://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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(12))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ 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_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:

INVESTMENTS - INVESTMENT IN KUKIO RESORT LAND DEVELOPMENT PARTNERSHIP (Details) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 27, 2013 USD ($) partnership	Mar. 31, 2023 USD ($) lot	Mar. 31, 2022 USD ($)	Mar. 31, 2023 USD ($) lot	Mar. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 07, 2019
Investment Holdings [Line Items]
Equity in income of affiliates		$ 0	$ 1,760	$ 538	$ 2,967
Investment in land development partnerships
Investment Holdings [Line Items]
Number of limited liability limited partnerships formed \| partnership	2
Cash distribution from equity method investment, gross		0	1,760	538	2,967
Cash distribution from equity method investment, net			1,568	478	2,643
Equity in income of affiliates		$ 0	1,760	538	2,967
Investment in Kukio Resort Land Development Partnerships							$ 0
Cumulative cash distributions from Kukio Resort Land Development Partnerships in excess of our investment balance				$ 1,211		$ 958
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		1		1
KD Kaupulehu, LLLP \| KD Acquisition II, LP \| Investment in land development partnerships
Investment Holdings [Line Items]
Ownership interest acquired								55.00%
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			$ 192	$ 60	$ 324