Gain (Loss) on Disposition of Assets, Reversal of Lease Liability in Excess of the Right-of-use Asset

No definition available.

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

- Definition

Operating Lease, Area Of Land

+ References

No definition available.

+ Details

Name:	brn_OperatingLeaseAreaOfLand
Namespace Prefix:	brn_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Proceeds From Sale Of Operating Leased Assets

+ References

No definition available.

+ Details

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

- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnDispositionOfAssets1
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_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201602Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LEASES AND GAIN ON SALE OF ASSET - NARRATIVE (Details) $ in Thousands	1 Months Ended	3 Months Ended			9 Months Ended
	Mar. 31, 2020 USD ($) a	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($) a	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Oct. 01, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		$ 272			$ 272
Present value of lease liabilities		278			278
Operating lease, area of land \| a	0.75		0.75
Proceeds from the sale of asset	$ 1,100				1,100	$ 0
Gain on sale of asset		$ 0	$ 1,336	$ 0	$ 1,336	$ 0
Gain from the reversal of the storage yard's lease liability in excess of the right-of-use asset			$ 236
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets							$ 2,589
Present value of lease liabilities							$ 2,589