Contracts Revenue, Percent

No definition available.

Name:	orn_ContractsRevenuePercent
Namespace Prefix:	orn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of customers exceeding the 10% benchmark percentage.

+ References

No definition available.

+ Details

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

- Definition

Trade Accounts Receivable and Contract Receivable Retainage, Gross

+ References

No definition available.

+ Details

Name:	orn_TradeAccountsReceivableAndContractReceivableRetainageGross
Namespace Prefix:	orn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Trade Accounts Receivable and Contract Receivable Retainage, Net

+ References

No definition available.

+ Details

Name:	orn_TradeAccountsReceivableAndContractReceivableRetainageNet
Namespace Prefix:	orn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of allowance for credit loss on accounts receivable, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-4

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 954
-SubTopic 310
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481027/954-310-50-2

+ Details

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

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-21

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-20

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482861/275-10-50-18

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482861/275-10-50-20

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479941/924-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_StatementGeographicalAxis=us-gaap_NonUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=orn_TradeAndContractRetainageReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	orn_CustomerByTypeAxis=orn_CustomerTypeFederalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=orn_CustomerOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	orn_CustomerByTypeAxis=orn_CustomerTypeStateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	orn_CustomerByTypeAxis=orn_CustomerTypeLocalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	orn_CustomerByTypeAxis=orn_CustomerTypePrivateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Concentration of Risk and Enterprise-Wide Disclosures (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023 USD ($) customer	Jun. 30, 2022 USD ($) customer	Jun. 30, 2023 USD ($) customer	Jun. 30, 2022 USD ($) customer	Dec. 31, 2022 USD ($) customer
Concentration Risk [Line Items]
Allowance for credit losses	$ (576)		$ (576)		$ (606)
Contract revenues	$ 182,534	$ 194,575	$ 341,708	$ 369,506
Foreign
Concentration Risk [Line Items]
Contract revenues, percent	4.00%	1.00%	2.90%	0.70%
Customer concentration risk \| Trade and contract retainage receivables
Concentration Risk [Line Items]
Gross receivables	$ 168,818		$ 168,818		158,237
Allowance for credit losses	(576)		(576)		(606)
Net receivables	168,242		$ 168,242		$ 157,631
Number of customers exceeding the 10% benchmark percentage \| customer					0
Concentration risk, percentage			100.00%		100.00%
Customer concentration risk \| Contract revenues
Concentration Risk [Line Items]
Number of customers exceeding the 10% benchmark percentage \| customer		0	0	0
Contract revenues	$ 182,534	$ 194,575	$ 341,708	$ 369,506
Contract revenues, percent	100.00%	100.00%	100.00%	100.00%
Customer concentration risk \| Federal Government \| Trade and contract retainage receivables
Concentration Risk [Line Items]
Gross receivables	$ 26,878		$ 26,878		$ 4,612
Number of customers exceeding the 10% benchmark percentage \| customer			1
Concentration risk, percentage			16.00%		3.00%
Customer concentration risk \| Federal Government \| Trade and contract retainage receivables \| Customer One
Concentration Risk [Line Items]
Concentration risk, percentage			13.00%
Customer concentration risk \| Federal Government \| Contract revenues
Concentration Risk [Line Items]
Number of customers exceeding the 10% benchmark percentage \| customer	1
Contract revenues	$ 44,416	$ 19,834	$ 67,472	$ 42,529
Contract revenues, percent	24.00%	10.00%	20.00%	12.00%
Customer concentration risk \| Federal Government \| Contract revenues \| Customer One
Concentration Risk [Line Items]
Contract revenues, percent	14.00%
Customer concentration risk \| State Governments \| Trade and contract retainage receivables
Concentration Risk [Line Items]
Gross receivables	$ 2,740		$ 2,740		$ 3,111
Concentration risk, percentage			2.00%		2.00%
Customer concentration risk \| State Governments \| Contract revenues
Concentration Risk [Line Items]
Contract revenues	$ 14,176	$ 13,753	$ 32,504	$ 21,457
Contract revenues, percent	8.00%	7.00%	10.00%	5.00%
Customer concentration risk \| Local Governments \| Trade and contract retainage receivables
Concentration Risk [Line Items]
Gross receivables	$ 19,139		$ 19,139		$ 16,197
Concentration risk, percentage			11.00%		10.00%
Customer concentration risk \| Local Governments \| Contract revenues
Concentration Risk [Line Items]
Contract revenues	$ 21,693	$ 26,198	$ 42,381	$ 58,600
Contract revenues, percent	12.00%	14.00%	12.00%	16.00%
Customer concentration risk \| Private Companies \| Trade and contract retainage receivables
Concentration Risk [Line Items]
Gross receivables	$ 120,061		$ 120,061		$ 134,317
Concentration risk, percentage			71.00%		85.00%
Customer concentration risk \| Private Companies \| Contract revenues
Concentration Risk [Line Items]
Contract revenues	$ 102,249	$ 134,790	$ 199,351	$ 246,920
Contract revenues, percent	56.00%	69.00%	58.00%	67.00%