Number of indefinite-lived intangible assets held by the entity.

No definition available.

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Namespace Prefix:	orn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of assets held-for-sale that are not part of a disposal group.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482309/360-10-15-4

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwillAbstract
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- 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

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_VehiclesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

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Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_MarineServicesEquipmentMember
Namespace Prefix:
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- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_OfficeEquipmentMember
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- Details

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Summary of Significant Accounting Principles - Property and Equipment (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) Asset	Dec. 31, 2023 USD ($)
Property, Plant and Equipment
Assets classified as held-for-sale \| $	$ 0.8	$ 0.0
Infinite-lived intangible assets
Number of infinite-lived intangible assets \| Asset	1
Equipment improvement \| Minimum
Property, Plant and Equipment
Property and equipment useful life		3 years
Equipment improvement \| Maximum
Property, Plant and Equipment
Property and equipment useful life		10 years
Automobiles and trucks \| Minimum
Property, Plant and Equipment
Property and equipment useful life		3 years
Automobiles and trucks \| Maximum
Property, Plant and Equipment
Property and equipment useful life		10 years
Building and improvements \| Minimum
Property, Plant and Equipment
Property and equipment useful life		10 years
Building and improvements \| Maximum
Property, Plant and Equipment
Property and equipment useful life		30 years
Construction equipment \| Minimum
Property, Plant and Equipment
Property and equipment useful life		3 years
Construction equipment \| Maximum
Property, Plant and Equipment
Property and equipment useful life		10 years
Vessels and other equipment \| Minimum
Property, Plant and Equipment
Property and equipment useful life		3 years
Vessels and other equipment \| Maximum
Property, Plant and Equipment
Property and equipment useful life		40 years
Office equipment \| Minimum
Property, Plant and Equipment
Property and equipment useful life		3 years
Office equipment \| Maximum
Property, Plant and Equipment
Property and equipment useful life		5 years
Dry-docking capitalized costs \| Minimum
Property, Plant and Equipment
Property and equipment useful life		3 years
Dry-docking capitalized costs \| Maximum
Property, Plant and Equipment
Property and equipment useful life		7 years