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LEASES - As Lessor - Lease Termination Fees (Details) - USD ($) | 1 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2021 | Dec. 31, 2020
Retail tenants |  |
Lease Termination Fee |  |
Payments received upon early lease termination | $ 350,000 |
Industrial tenants |  |
Lease Termination Fee |  |
Payments received upon early lease termination |  | $ 88,000

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- Definition n/a + References No definition available. + Details
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Namespace Prefix: | olp_
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Balance Type: | na
Period Type: | duration

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- Definition The cash inflow attributable to a tenant's early lease termination. + References No definition available. + Details
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Namespace Prefix: | olp_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |