Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt (Schedule of Lines of Credit) (Details)

v2.4.1.9
Long-Term Debt (Schedule of Lines of Credit) (Details) (USD $)
Mar. 31, 2015
Sep. 30, 2014
Jun. 30, 2014
Line of Credit Facility [Line Items]      
Lines of Credit $ 21,975,000us-gaap_LineOfCredit $ 3,160,000us-gaap_LineOfCredit  
Metropolitan Life Insurance Company and New England Life Insurance Company revolving line of credit [Member]      
Line of Credit Facility [Line Items]      
Lines of Credit        
Amount of credit facility 25,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_MetropolitanLifeInsuranceCompanyAndNewEnglandLifeInsuranceCompanyRevolvingLineOfCreditMember
   
Interest rate at end of period 1.75%us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
/ us-gaap_DebtInstrumentAxis
= alco_MetropolitanLifeInsuranceCompanyAndNewEnglandLifeInsuranceCompanyRevolvingLineOfCreditMember
   
Working Capital Line of Credit [Member]      
Line of Credit Facility [Line Items]      
Lines of Credit 16,239,000us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= alco_WorkingCapitalLineOfCreditMember
    
Amount of credit facility 70,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_WorkingCapitalLineOfCreditMember
   
Interest rate at end of period 1.92%us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
/ us-gaap_DebtInstrumentAxis
= alco_WorkingCapitalLineOfCreditMember
   
Remaining available credit 36,300,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_WorkingCapitalLineOfCreditMember
   
Rabo Agrifinance, Inc. revolving line of credit [Member]      
Line of Credit Facility [Line Items]      
Lines of Credit        
Amount of credit facility 60,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_RaboAgrifinanceIncRevolvingLineOfCreditMember
   
Interest rate at end of period 2.10%us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
/ us-gaap_DebtInstrumentAxis
= alco_RaboAgrifinanceIncRevolvingLineOfCreditMember
   
Remaining available credit 60,000,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_RaboAgrifinanceIncRevolvingLineOfCreditMember
   
Prudential Mortgage Capital Company, LLC revolving line of credit [Member]      
Line of Credit Facility [Line Items]      
Lines of Credit 5,736,000us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember
3,160,000us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember
3,160,000us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember
Amount of credit facility 6,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember
   
Interest rate at end of period 3.00%us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember
  2.98%us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember
Remaining available credit $ 264,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember
  $ 2,840,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= alco_PrudentialMortgageCapitalCompanyLlcRevolvingLineOfCreditMember