Quarterly report pursuant to Section 13 or 15(d)

Property, Buildings and Equipment, Net (Schedule of Property, Buildings and Equipment) (Details)

v2.4.1.9
Property, Buildings and Equipment, Net (Schedule of Property, Buildings and Equipment) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Sep. 30, 2014
Property, Plant and Equipment [Line Items]    
Net property, buildings and equipment $ 337,597us-gaap_PropertyPlantAndEquipmentNet $ 87,432us-gaap_PropertyPlantAndEquipmentNet
Depreciable Property Plant and Equipment [Member]    
Property, Plant and Equipment [Line Items]    
Gross property, buildings and equipment 295,236us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_DepreciablePropertyPlantAndEquipmentMember
122,534us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_DepreciablePropertyPlantAndEquipmentMember
Less accumulated depreciation and depletion (64,473)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_DepreciablePropertyPlantAndEquipmentMember
(63,031)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_DepreciablePropertyPlantAndEquipmentMember
Net property, buildings and equipment 230,763us-gaap_PropertyPlantAndEquipmentNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_DepreciablePropertyPlantAndEquipmentMember
59,503us-gaap_PropertyPlantAndEquipmentNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_DepreciablePropertyPlantAndEquipmentMember
Breeding herd [Member]    
Property, Plant and Equipment [Line Items]    
Gross property, buildings and equipment 11,032us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BreedingAndProductionAnimalsMember
11,558us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BreedingAndProductionAnimalsMember
Buildings [Member]    
Property, Plant and Equipment [Line Items]    
Gross property, buildings and equipment 18,545us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingMember
15,220us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingMember
Citrus trees [Member]    
Property, Plant and Equipment [Line Items]    
Gross property, buildings and equipment 215,704us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_CitrusTreesMember
45,257us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= alco_CitrusTreesMember
Equipment and Other Facilities [Member]    
Property, Plant and Equipment [Line Items]    
Gross property, buildings and equipment 49,955us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_MachineryAndEquipmentMember
50,499us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_MachineryAndEquipmentMember
Land and Land Improvements [Member]    
Property, Plant and Equipment [Line Items]    
Gross property, buildings and equipment $ 106,834us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandAndLandImprovementsMember
$ 27,929us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandAndLandImprovementsMember