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Real Estate Investments - Additional Information (Detail) (USD $)
 3 Months Ended 0 Months Ended
Mar. 31, 2015
Feb. 26, 2015
Jan. 05, 2015
Jan. 09, 2015
Feb. 13, 2015
Apr. 08, 2015
Real Estate Properties [Line Items]            
Sale of office property $ 15,224,000us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment          
Land held for development purchased 1,180,000us-gaap_LandAvailableForDevelopment          
Whetstone Apartments [Member]            
Real Estate Properties [Line Items]            
Proceeds from sale of Whetstone Apartments   35,600,000us-gaap_ProceedsFromSaleOfBuildings
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_WhetstoneApartmentsMember		        
Sentara Williamsburg [Member]            
Real Estate Properties [Line Items]            
Sale of office property     15,400,000us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_SentaraWilliamsburgMember		      
Net proceeds after transaction costs and tax protection payments     15,200,000ahh_NetProceedsAfterTransactionCostsAndTaxProtectionPayments
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_SentaraWilliamsburgMember		      
Gain (Loss) on disposition of Virginia Natural Gas office property     6,200,000us-gaap_GainLossOnSaleOfOilAndGasProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_SentaraWilliamsburgMember		      
Myrtle Beach [Member]            
Real Estate Properties [Line Items]            
Area of property acquired       57,000us-gaap_AreaOfLand
/ us-gaap_BusinessAcquisitionAxis
= ahh_MyrtleBeachMember		    
Acquisition, cash consideration       8,700,000us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= ahh_MyrtleBeachMember		    
Acquisition, assumption of debt       5,100,000us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred
/ us-gaap_BusinessAcquisitionAxis
= ahh_MyrtleBeachMember		    
Oyster Point [Member]            
Real Estate Properties [Line Items]            
Sale of office property         6,500,000us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment
/ us-gaap_BusinessAcquisitionAxis
= ahh_OysterPointMember		  
Stone House Square And Mary Land And Perry Hall Market Place [Member]            
Real Estate Properties [Line Items]            
Acquisition date Apr. 08, 2015          
Stone House Square And Mary Land And Perry Hall Market Place [Member] | Subsequent Event [Member]            
Real Estate Properties [Line Items]            
Acquisition, cash consideration           35,400,000us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= ahh_StoneHouseSquareAndMaryLandAndPerryHallMarketPlaceMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Net proceeds from sale of common stock (in shares)           415,500us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
/ us-gaap_BusinessAcquisitionAxis
= ahh_StoneHouseSquareAndMaryLandAndPerryHallMarketPlaceMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Stone House Square And Mary Land And Perry Hall Market Place [Member] | Subsequent Event [Member] | Sentara Williamsburg [Member]            
Real Estate Properties [Line Items]            
Net proceeds after transaction costs and tax protection payments           15,200,000ahh_NetProceedsAfterTransactionCostsAndTaxProtectionPayments
/ us-gaap_BusinessAcquisitionAxis
= ahh_StoneHouseSquareAndMaryLandAndPerryHallMarketPlaceMember
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= ahh_SentaraWilliamsburgMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Virginia Beach, VA [Member]            
Real Estate Properties [Line Items]            
Land held for development purchased $ 1,200,000us-gaap_LandAvailableForDevelopment
/ us-gaap_BusinessAcquisitionAxis
= ahh_VirginiaBeachVaMember