XML 34 R35.htm IDEA: XBRL DOCUMENT v2.4.1.9
Property and Equipment (Details) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross $ 282,638,000us-gaap_PropertyPlantAndEquipmentGross   $ 277,901,000us-gaap_PropertyPlantAndEquipmentGross
Less: accumulated depreciation (166,282,000)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment   (161,276,000)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Net book value of depreciable assets 116,356,000orn_PropertyPantandEquipmentNetBookValueofDepreciableAssets   116,625,000orn_PropertyPantandEquipmentNetBookValueofDepreciableAssets
Property and equipment, net 162,057,000us-gaap_PropertyPlantAndEquipmentNet   161,773,000us-gaap_PropertyPlantAndEquipmentNet
Depreciation expense 5,400,000us-gaap_Depreciation 5,600,000us-gaap_Depreciation  
Payments to acquire property and equipment 5,712,000us-gaap_PaymentsToAcquirePropertyPlantAndEquipment 2,005,000us-gaap_PaymentsToAcquirePropertyPlantAndEquipment  
Automobiles and trucks      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 2,209,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_VehiclesMember
  2,006,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_VehiclesMember
Building and improvements      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 28,726,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingAndBuildingImprovementsMember
  28,641,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingAndBuildingImprovementsMember
Construction equipment      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 147,221,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= orn_ConstructionEquipmentMember
  146,088,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= orn_ConstructionEquipmentMember
Dredges and dredging equipment      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 99,491,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_MarineServicesEquipmentMember
  96,275,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_MarineServicesEquipmentMember
Office equipment      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 4,991,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OfficeEquipmentMember
  4,891,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OfficeEquipmentMember
Construction in progress      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross 5,827,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember
  5,274,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember
Land      
Property, Plant and Equipment [Line Items]      
Property, plant and equipment, gross $ 39,874,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandMember
  $ 39,874,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandMember