v3.22.2.2

Credit Risk Concentrations - Additional Information (Detail) - Customer | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Concentration Risk [Line Items] |  |  |  |
Number of tenants or common franchises | 0 | 0 | 0 | 0

X
- Definition Number of major customer. + References No definition available. + Details
Name: | bnl_NumberOfMajorCustomer
Namespace Prefix: | bnl_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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 No definition available. + Details
Name: | us-gaap_ConcentrationRiskLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration