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Indebtedness - Additional Information (Detail) (USD $)
 0 Months Ended 12 Months Ended 0 Months Ended
Nov. 03, 2014
Dec. 31, 2014
Feb. 28, 2014
Aug. 28, 2014
Nov. 14, 2014
Jan. 23, 2015
Feb. 20, 2015
Sep. 15, 2014
May 22, 2013
Jan. 17, 2014
Aug. 15, 2014
Oct. 10, 2013
May 13, 2013
Dec. 31, 2013
Jun. 13, 2014
Debt Instrument [Line Items]                              
Repayment of credit facility $ 1,000,000us-gaap_RepaymentsOfLinesOfCredit                            
Credit facility maximum commitment amount   200,000,000ahh_LoanFacilityMaximumCommitmentAmount                          
Line of credit facility covenant terms   The new credit facility limits the Company’s ability to pay cash dividends. However, so long as no default or event of default exists, the credit agreement allows the Company to pay cash dividends with respect to any 12-month period in an amount not to exceed the greater of: (i) 95% of adjusted funds from operations (as defined in the credit agreement) or (ii) the amount required for the Company (a) to maintain its status as a REIT and (b) to avoid income or excise tax. If certain defaults or events of default exist, the Company may pay cash dividends with respect to any 12-month period to the extent necessary to maintain its status as a REIT.                          
Percentage of adjusted funds from operations   95.00%ahh_PercentageOfAdjustedFundsFromOperation                          
Repayment date of debt instrument   Feb. 20, 2015                          
Oceaneering [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Feb. 28, 2018                          
Oceaneering [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   1.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_OceaneeringInternationalFacilityMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Lightfoot Marketplace [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Nov. 14, 2017                          
Lightfoot Marketplace [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   1.90%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_LightfootMarketplaceMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Construction Loans [Member] | Oceaneering [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Feb. 28, 2018                          
Debt, face value     19,500,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_OceaneeringInternationalFacilityMember		                        
Construction Loans [Member] | Oceaneering [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate     1.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_OceaneeringInternationalFacilityMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                        
Construction Loans [Member] | Commonwealth of Virginia [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Aug. 28, 2017                          
Debt, face value       5,400,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_CommonwealthVirginiaMember		                      
Construction Loans [Member] | Commonwealth of Virginia [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate       1.90%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_CommonwealthVirginiaMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                      
Construction Loans [Member] | Lightfoot Marketplace [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Nov. 14, 2017                          
Debt, face value         15,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_LightfootMarketplaceMember		                    
Construction Loans [Member] | Lightfoot Marketplace [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate         1.90%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_LightfootMarketplaceMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                    
New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Credit facility maximum commitment amount   350,000,000ahh_LoanFacilityMaximumCommitmentAmount
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember		                          
Unencumbered borrowing base properties, percentage   60.00%us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember		                          
Debt service coverage ratio   1.50%ahh_DebtServiceCoverageRatio
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember		                          
Subsequent Event [Member]                              
Debt Instrument [Line Items]                              
Amount borrowed under credit facility           5,000,000us-gaap_ProceedsFromLinesOfCredit
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                  
Maximum [Member] | Subsequent Event [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate             1.95%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                
Minimum [Member] | Subsequent Event [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate             1.35%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                
Revolving Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Financial covenant, minimum fixed charge coverage ratio   175.00%ahh_DebtInstrumentCovenantMinimumFixedChargeCoverageRatio
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember		                          
Financial covenant, minimum tangible net worth   At least the sum of 80% of tangible net worth on the closing date of the credit facility plus 75% of the net proceeds of any additional equity issuances                          
Debt instrument maturity date   May 13, 2016                          
Revolving Credit Facility [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Feb. 20, 2019                          
Revolving credit facility, extension option   1 year                          
Revolving Credit Facility [Member] | Maximum [Member]                              
Debt Instrument [Line Items]                              
Financial covenant, maximum leverage ratio as of the last day of each fiscal quarter   65.00%ahh_LineOfCreditFacilityCovenantComplianceLeverageRatio
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Financial covenant, maximum amount of variable rate indebtedness   30.00%ahh_LineOfCreditFacilityCovenantVariableRateIndebtednessToAssetValue
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Financial covenant, maximum amount of secured recourse indebtedness   35.00%ahh_LineOfCreditFacilityCovenantSecuredRecourseIndebtednessToAssetValue
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Financial covenant, investments to total asset value   30.00%ahh_LineOfCreditFacilityCovenantInvestmentToAssetValue
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Revolving Credit Facility [Member] | Maximum [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   2.20%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Revolving Credit Facility [Member] | Maximum [Member] | New Credit Facility [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   2.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Revolving Credit Facility [Member] | Maximum [Member] | Unimproved Land Holdings [Member]                              
Debt Instrument [Line Items]                              
Financial covenant, investments to total asset value   5.00%ahh_LineOfCreditFacilityCovenantInvestmentToAssetValue
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= ahh_LandUnimprovedMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Revolving Credit Facility [Member] | Maximum [Member] | Construction in Progress [Member]                              
Debt Instrument [Line Items]                              
Financial covenant, investments to total asset value   25.00%ahh_LineOfCreditFacilityCovenantInvestmentToAssetValue
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Revolving Credit Facility [Member] | Maximum [Member] | Unconsolidated Affiliates [Member]                              
Debt Instrument [Line Items]                              
Financial covenant, investments to total asset value   5.00%ahh_LineOfCreditFacilityCovenantInvestmentToAssetValue
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= ahh_UnconsolidatedAffiliatesMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Revolving Credit Facility [Member] | Minimum [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   1.60%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Revolving Credit Facility [Member] | Minimum [Member] | New Credit Facility [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   1.40%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Term Loan Facility [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Feb. 20, 2020                          
Term Loan Facility [Member] | Maximum [Member] | New Credit Facility [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   1.95%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= ahh_TermLoanFacilityMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Term Loan Facility [Member] | Minimum [Member] | New Credit Facility [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   1.35%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= ahh_TermLoanFacilityMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Operating Partnership [Member]                              
Debt Instrument [Line Items]                              
Aggregate capacity under the credit facility                       155,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		 100,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		    
Credit facility, amount outstanding   59.0us-gaap_LineOfCredit
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		                          
Repayment of credit facility               49,000,000us-gaap_RepaymentsOfLinesOfCredit
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		              
Repayment of other indebtedness                 150,000,000us-gaap_RepaymentsOfOtherDebt
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		            
Operating Partnership [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Financial covenant, minimum tangible net worth   Tangible net worth of not less than the sum of $220.0 million and 75% of the net equity proceeds received after December 31, 2014                          
Financial covenant, minimum tangible net worth amount   220,000,000ahh_LineOfCreditFacilityFinancialCovenantMinimumTangibleNetWorth
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember		                          
Operating Partnership [Member] | Subsequent Event [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Amount borrowed under credit facility             54,000,000us-gaap_ProceedsFromLinesOfCredit
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                
Repayment of term loan facility             50,000,000us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                
Repayment of other indebtedness             39,000,000us-gaap_RepaymentsOfOtherDebt
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                
Operating Partnership [Member] | Maximum [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Financial covenant, maximum leverage ratio as of the last day of each fiscal quarter   60.00%ahh_LineOfCreditFacilityCovenantComplianceLeverageRatio
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Financial covenant, maximum amount of variable rate indebtedness   30.00%ahh_LineOfCreditFacilityCovenantVariableRateIndebtednessToAssetValue
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Financial covenant, maximum amount of secured recourse indebtedness   45.00%ahh_LineOfCreditFacilityCovenantSecuredRecourseIndebtednessToAssetValue
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Unused commitment fee   0.25%us-gaap_LineOfCreditFacilityCommitmentFeePercentage
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Financial covenant, maximum amount of secured recourse debt   25.00%ahh_LineOfCreditFacilityCovenantSecuredRecourseDebtToAssetValue
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		                          
Operating Partnership [Member] | Minimum [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Unused commitment fee   0.15%us-gaap_LineOfCreditFacilityCommitmentFeePercentage
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		                          
Ratio of adjusted EBITDA to fixed charges   150.00%ahh_AdjustedEbitdaMargin
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		                          
Operating Partnership [Member] | Revolving Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Aggregate capacity under the credit facility   155,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		                          
Credit facility, amount outstanding                           70,000,000us-gaap_LineOfCredit
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		  
Amount borrowed under credit facility   38,000,000us-gaap_ProceedsFromLinesOfCredit
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		                          
Debt instrument maturity date   May 13, 2016                          
Interest rate on credit facility as of end of period   1.92%us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		                          
Operating Partnership [Member] | Revolving Credit Facility [Member] | Maximum [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   2.20%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Operating Partnership [Member] | Revolving Credit Facility [Member] | Minimum [Member] | LIBOR [Member]                              
Debt Instrument [Line Items]                              
Stated interest rate, basis spread on variable rate   1.60%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
Operating Partnership [Member] | Senior Unsecured Credit Facility [Member] | Subsequent Event [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Aggregate capacity under the credit facility             200,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= ahh_SeniorUnsecuredCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                
Operating Partnership [Member] | Senior Unsecured Revolving Credit Facility [Member] | Subsequent Event [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Aggregate capacity under the credit facility             150,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= ahh_SeniorUnsecuredRevolvingCreditFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                
Operating Partnership [Member] | Senior Unsecured Term Loan Facility [Member] | Subsequent Event [Member] | New Credit Facility [Member]                              
Debt Instrument [Line Items]                              
Aggregate capacity under the credit facility             50,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= ahh_SeniorUnsecuredTermLoanFacilityMember
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
/ us-gaap_LongtermDebtTypeAxis
= ahh_NewCreditFacilityMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                
Liberty Apartments [Member]                              
Debt Instrument [Line Items]                              
Debt instrument maturity date   Nov. 01, 2043                          
Acquisition, assumption of debt                   17,000,000us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred
/ us-gaap_BusinessAcquisitionAxis
= ahh_LibertyApartmentsMember		          
Fair value adjustment of debt of liberty apartment                   (1,500,000)ahh_BusinessCombinationFairValueAdjustmentToDebtAssumed
/ us-gaap_BusinessAcquisitionAxis
= ahh_LibertyApartmentsMember		          
Outstanding principal amount of debt                   18,500,000ahh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongtermDebtIncludingFairValueAdjustment
/ us-gaap_BusinessAcquisitionAxis
= ahh_LibertyApartmentsMember		          
Loans available under Liberty Apartments loan                             2,400,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther
/ us-gaap_BusinessAcquisitionAxis
= ahh_LibertyApartmentsMember
Debt assumed, interest rate                   5.66%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_BusinessAcquisitionAxis
= ahh_LibertyApartmentsMember		          
Debt assumed, term                   30 years          
Dimmock Square [Member]                              
Debt Instrument [Line Items]                              
Defeased loan                     $ 10,100,000ahh_DefeasedDebt
/ us-gaap_BusinessAcquisitionAxis
= ahh_DimmockSquareMember