Name:	olp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharesNotEarnedDueToMetricsNotMet
Namespace Prefix:	olp_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_AwardDateAxis=olp_AwardsGrantedIn2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_VestingAxis=olp_ShareBasedPaymentArrangementVestingJune302025Member
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_AwardDateAxis=olp_AwardsGrantedIn2021Member
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Data Type:	na
Balance Type:
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Name:	us-gaap_VestingAxis=olp_ShareBasedPaymentArrangementVestingJune302024Member
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_AwardDateAxis=olp_AwardsGrantedIn2020Member
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_VestingAxis=olp_ShareBasedPaymentArrangementVestingJune302023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AwardDateAxis=olp_AwardsGrantedIn2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Namespace Prefix:
Data Type:	na
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Name:	us-gaap_AwardDateAxis=olp_AwardsGrantedIn2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
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