Debt Instrument, Carrying Amount, Current

No definition available.

Name:	orn_DebtInstrumentCarryingAmountCurrent
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Carrying Amount Noncurrent

+ References

No definition available.

+ Details

Name:	orn_DebtInstrumentCarryingAmountNoncurrent
Namespace Prefix:	orn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

+ Details

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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

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of debt issuance costs that were incurred during a noncash or partial noncash transaction.

+ References

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

- Definition

Represents the charge against earnings during the period for commitment fees and debt issuance expenses.

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs classified as current. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Balance Type:	debit
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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Name:	us-gaap_LongTermDebtNoncurrent
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Balance Type:	credit
Period Type:	instant

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=orn_TermLoanMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=orn_RevolvingCreditFacility364DayMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

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Long-term Debt and Line of Credit - Obligations under Debt Arrangements (Details) - USD ($) $ in Thousands			1 Months Ended
	Oct. 09, 2020	Jun. 08, 2020	May 31, 2019	Mar. 31, 2019	Jul. 31, 2018	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Principal current						$ 39,141	$ 4,500
Principal, long-term						259	30,586
Principal						39,400	35,086
Deferred Issuance Costs, current							(156)
Deferred Issuance Costs, long-term							(1,063)
Debt Issuance Costs, Net, Total							(1,219)
Net Value, current						39,141	4,344
Net Value, long-term						259	29,523
Total debt						$ 39,400	33,867
Line of Credit
Debt Instrument [Line Items]
Weighted average interest rate						2.60%
Other Debt
Debt Instrument [Line Items]
Principal current						$ 141
Principal, long-term						259
Principal						400
Net Value, current						141
Net Value, long-term						259
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity						50,000
Principal current						39,000
Net Value, current						$ 39,000
Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Debt issuance expense			$ 400
Principal, long-term							5,000
Deferred Issuance Costs, long-term							(174)
Net Value, long-term							4,826
Term Loan \| Line of Credit
Debt Instrument [Line Items]
Principal current							4,500
Principal, long-term							25,586
Deferred Issuance Costs, current							(156)
Deferred Issuance Costs, long-term							(889)
Net Value, current							4,344
Net Value, long-term							24,697
364-Day Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 20,000
Borrowings							0
364-Day Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Credit facility term		364 days
Fourth, Fifth And Sixth Amendments To Credit Agreement
Debt Instrument [Line Items]
Debt Issuance Costs, Net, Total							$ (900)
Fourth Amendment to Credit Agreement \| Line of Credit
Debt Instrument [Line Items]
Debt issuance cost					$ 900
Fifth Amendment To Credit Agreement \| Line of Credit
Debt Instrument [Line Items]
Debt issuance cost				$ 600
Sixth Amendment To Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			50,000
Sixth Amendment To Credit Agreement \| Line of Credit
Debt Instrument [Line Items]
Debt issuance cost			$ 900
Eighth Amendment to Credit Agreement \| Line of Credit
Debt Instrument [Line Items]
Debt issuance cost	$ 0