Represents the fees related to sale of interest in leasehold land.

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the number of development increments from which lots and/or residential units will be sold.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Definition

Represents the number of single-family lots sold to date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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Period Type:	duration

- Definition

Percentage of gross sales proceeds from the sale of lots within Increment II of Kaupulehu Increment II.

+ References

No definition available.

+ Details

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- Definition

The gross cash inflow from the sale of interest in leasehold land.

+ References

No definition available.

+ Details

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

- Definition

Net revenue from the sale of interest in leasehold land.

+ References

No definition available.

+ Details

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

- Definition

Area of land held.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfLand
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- 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

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- Details

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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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INVESTMENTS - PERCENTAGE OF SALES PAYMENTS (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2016 USD ($) lot	Mar. 31, 2016 USD ($) a increment	Mar. 31, 2015 USD ($)	Mar. 31, 2016 USD ($) a	Mar. 31, 2015 USD ($)
Investment Holdings [Line Items]
Sale of interest in leasehold land, net		$ 284	$ 817	$ 413	$ 1,849
Kaupulehu Developments
Investment Holdings [Line Items]
Area of land (in acres) \| a		870		870
Number of development increments \| increment		2
Fees Related to Sale of Interest in Leasehold Land		$ (46)	(133)	$ (67)	(301)
Sale of interest in leasehold land, net		284	817	413	1,849
Percentage of sales payment received		$ 330	$ 950	$ 480	$ 2,150
Land Interest
Investment Holdings [Line Items]
Area of land (in acres) \| a		1,000		1,000
Increment II \| Subsequent Event \| Kaupulehu Developments
Investment Holdings [Line Items]
Percentage of sales payment received	$ 1,600
Percentage of gross proceeds	8.00%
Number of single family lots sold \| lot	1