Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities
Net (loss) income	$ (9,498)	$ 1,587
Adjustments to reconcile net loss to net cash provided by
Depreciation and amortization	18,831	17,631
Bad debt expense	67	261
Deferred income taxes	(2,665)	0
Stock-based compensation	1,750	1,098
Gain (loss) on sale of property and equipment	2,007	(165)
Change in operating assets and liabilities:
Accounts receivable	(33,000)	918
Income tax receivable	233	0
Inventory	(397)	(1,257)
Prepaid expenses and other	(3,266)	1,038
Costs and estimated earnings in excess of billings on uncompleted contracts	1,440	(13,815)
Accounts payable	10,114	5,188
Accrued liabilities	6,271	4,765
Income tax payable	(1,891)	703
Billings in excess of costs and estimated earnings on uncompleted contracts	7,417	1,354
Deferred revenue	(34)	(44)
Net cash (used in) provided by operating activities	(2,621)	19,262
Cash flows from investing activities:
Proceeds from sale of property and equipment	667	441
Purchase of land	0	(22,199)
Purchase of property and equipment	(13,577)	(18,131)
Net cash (used in) investing activities	(125,244)	(39,889)
Cash flows from financing activities:
Borrowings from Credit Facility	149,021	26,000
Payments made on borrowings from Credit Facility	(6,268)	(1,168)
Extinguishment of debt	(32,427)	0
Exercise of stock options	28	794
Purchase of shares into treasury	(3,101)	0
Net cash provided by financing activities	107,253	25,626
Net change in cash and cash equivalents	(20,612)	4,999
Cash and cash equivalents at beginning of period	38,893	40,859
Cash and cash equivalents at end of period	18,281	45,858
Supplemental disclosures of cash flow information, cash paid during the period for:
Interest	978	459
Taxes (net of refunds)	490	262
TAS Commercial Concrete
Cash flows from investing activities:
Payments to acquire businesses	(111,977)	0
Houston Industrial Tool Services, Inc.
Cash flows from investing activities:
Payments to acquire businesses	$ (357)	$ 0

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=orn_TASCommercialConcreteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=orn_HoustonIndustrialToolServicesInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: