Amount of difference between the carrying amount and the sales price of real estate properties sold.

No definition available.

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Period Type:	duration

- Definition

Gross proceeds received from the sale of real estate during the current period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The cash outflow to repay long-term debt that is wholly or partially secured by collateral upon sale of the property.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Income (loss) from sale of consolidated JV property attributable to noncontrolling interest.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

The amount of reduction to gain on sale of properties attributable to write-off of other assets.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of unbilled rent receivable written off during the period relating to properties sold.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of write-off of net unamortized intangible lease assets.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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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

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- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481203/810-10-50-5A

+ Details

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Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=olp_LandLocatedInLakewoodColoradoMember
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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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SALES OF PROPERTIES (Details) - USD ($) $ in Thousands				3 Months Ended
SALES OF PROPERTIES (Details) - USD ($) $ in Thousands	Jan. 21, 2025	Jan. 16, 2025	Mar. 06, 2024	Mar. 31, 2025	Mar. 31, 2024
SALES OF PROPERTIES
Gain on sale of real estate, net				$ 1,110	$ 1,784
Properties disposed of by sale
SALES OF PROPERTIES
Gross Sales Price				3,653	2,900
Gain on sale of real estate, net				$ 1,110	$ 1,784
Properties disposed of by sale \| Land and improvements in Lakewood, Colorado
SALES OF PROPERTIES
Gross Sales Price		$ 400
Gain on sale of real estate, net		(44)
Non-controlling interest's share of the gain		$ 4
Properties disposed of by sale \| Hooters restaurant property in Concord, North Carolina
SALES OF PROPERTIES
Gross Sales Price	$ 3,253
Gain on sale of real estate, net	1,154
Reduction to Gain on sale of real estate, net, attributable to the write-off of unbilled rent receivable	73
Reduction to Gain on sale of real estate, net, attributable to the write-off of net unamortized lease assets	$ 162
Properties disposed of by sale \| Hacienda Colorado restaurant parcel in Lakewood, Colorado
SALES OF PROPERTIES
Gross Sales Price			$ 2,900
Gain on sale of real estate, net			1,784
Non-controlling interest's share of the gain			178
Reduction to Gain on sale of real estate, net, attributable to the write-off of unbilled rent receivable			50
Reduction to Gain on sale of real estate, net, attributable to the write-off of other assets			$ 68
Consolidated VIE 1
SALES OF PROPERTIES
Ownership interest in consolidated joint venture of the company (as a percent)				90.00%
Consolidated VIE 1 \| Properties disposed of by sale \| Land and improvements in Lakewood, Colorado
SALES OF PROPERTIES
Ownership interest in consolidated joint venture of the company (as a percent)		90.00%
Consolidated VIE 1 \| Properties disposed of by sale \| Hacienda Colorado restaurant parcel in Lakewood, Colorado
SALES OF PROPERTIES
Ownership interest in consolidated joint venture of the company (as a percent)			90.00%
Mortgage prepaid on sale of real estate			$ 1,885
Consolidated VIE 2
SALES OF PROPERTIES
Ownership interest in consolidated joint venture of the company (as a percent)				95.00%