v3.24.3

Investment in Rental Property and Lease Arrangements - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2024 PropertyNumber Property	Sep. 30, 2024 PropertyNumber Property
Lessor Lease Description [Line Items]
Number of leased commercial properties owned | Property		773
Number of real estate properties under operating leases		760
Number of real estate properties under direct financing leases	9
Number of real estate properties under sales-type leases | Property	1
Number of real estate properties under direct financing leases that include land option	3
Lessee, operating lease, existence of option to extend	true
Lessee, finance lease, existence of option to extend	true
Minimum
Lessor Lease Description [Line Items]
Lessor operating lease, initial terms	10 years
Lessor direct financing leases, initial terms	10 years
Maximum
Lessor Lease Description [Line Items]
Lessor operating lease, initial terms	20 years
Lessor direct financing leases, initial terms	20 years

X

- Definition

Number of properties classified as direct financing leases.

+ References

No definition available.

+ Details

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X

- Definition

Number of properties classified as sales type lease leases.

+ References

No definition available.

+ Details

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Namespace Prefix:	bnl_
Data Type:	xbrli:integerItemType
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X

- Definition

Number of real estate properties under direct financing leases that include land option.

+ References

No definition available.

+ Details

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Namespace Prefix:	bnl_
Data Type:	xbrli:decimalItemType
Balance Type:	na
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X

- Definition

Indicates (true false) whether lessee has option to extend finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

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Period Type:	duration

X

- Definition

Indicates (true false) whether lessee has option to extend operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

X

- Definition

Term of lessor's direct financing lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-3

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X

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-3

+ Details

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X

- Definition

Term of lessor's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-3

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
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X

- Definition

The number of units (items of property) under operating lease arrangements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-13

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

+ Details

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Balance Type:	na
Period Type:	instant

X

- Details

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