Quarterly report pursuant to Section 13 or 15(d)

Assets Held for Sale (Details)

v2.4.1.9
Assets Held for Sale (Details) (USD $)
3 Months Ended 6 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Apr. 03, 2015
Sep. 30, 2014
Nov. 21, 2014
acre
Long Lived Assets Held-for-sale [Line Items]              
Assets held for sale $ 1,509,000us-gaap_DisposalGroupIncludingDiscontinuedOperationLongLivedAssets   $ 1,509,000us-gaap_DisposalGroupIncludingDiscontinuedOperationLongLivedAssets        
Sales price         1,509,000us-gaap_SignificantAcquisitionsAndDisposalsAcquisitionCostsOrSaleProceeds    
Gain (loss) on sale of real estate (116,000)us-gaap_GainsLossesOnSalesOfInvestmentRealEstate (1,000)us-gaap_GainsLossesOnSalesOfInvestmentRealEstate 16,424,000us-gaap_GainsLossesOnSalesOfInvestmentRealEstate (1,000)us-gaap_GainsLossesOnSalesOfInvestmentRealEstate      
Deferred gain on sale 29,140,000us-gaap_DeferredGainOnSaleOfProperty   29,140,000us-gaap_DeferredGainOnSaleOfProperty         
Asset impairment (541,000)us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf    (541,000)us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf         
Land and Land improvements [Member]              
Long Lived Assets Held-for-sale [Line Items]              
Assets held for sale 2,050,000us-gaap_DisposalGroupIncludingDiscontinuedOperationLongLivedAssets
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_CitrusLandAndLandImprovementsMember
  2,050,000us-gaap_DisposalGroupIncludingDiscontinuedOperationLongLivedAssets
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_CitrusLandAndLandImprovementsMember
       
Asset impairment     (541,000)us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_CitrusLandAndLandImprovementsMember
       
Hendry County Sugarcane Property [Member]              
Long Lived Assets Held-for-sale [Line Items]              
Acres held for sale             36,000alco_LongLivedAssetsHeldForSaleAcresOfLand
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_HendryCountySugarcanePropertyMember
Sales price             97,913,921us-gaap_SignificantAcquisitionsAndDisposalsAcquisitionCostsOrSaleProceeds
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_HendryCountySugarcanePropertyMember
Proceeds deposited with intermediary     97,126,000us-gaap_PaymentsForDelayedTaxExemptExchange
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_HendryCountySugarcanePropertyMember
       
Realized gain on disposal     42,753,000alco_DisposalGroupNotDiscontinuedOperationRealizedGainLossOnDisposal
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_HendryCountySugarcanePropertyMember
       
Gain (loss) on sale of real estate     13,613,000us-gaap_GainsLossesOnSalesOfInvestmentRealEstate
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_HendryCountySugarcanePropertyMember
       
Deferred gain on sale             $ 29,140,000us-gaap_DeferredGainOnSaleOfProperty
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_HendryCountySugarcanePropertyMember
Hendry County Sugarcane Property [Member] | Property Subject to Operating Lease [Member]              
Long Lived Assets Held-for-sale [Line Items]              
Acres held for sale             30,600alco_LongLivedAssetsHeldForSaleAcresOfLand
/ us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis
= alco_HendryCountySugarcanePropertyMember
/ us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis
= us-gaap_PropertySubjectToOperatingLeaseMember