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Business and Organization - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
 0 Months Ended 12 Months Ended 0 Months Ended
Sep. 15, 2014
May 22, 2013
Dec. 31, 2014
Parcels
May 13, 2013
Nov. 20, 2014
Real Estate Properties [Line Items]          
Common stock, shares issued 5,750,000us-gaap_StockIssuedDuringPeriodSharesNewIssues        
Net proceeds from Initial Public Offering   $ 192.2us-gaap_ProceedsFromIssuanceInitialPublicOffering      
Options to acquire developable lands, number of parcels of developable land to be acquired     9ahh_NumberOfParcelsOfLandToBeDeveloped    
Interest acquired     100.00%us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired    
IPO [Member]          
Real Estate Properties [Line Items]          
Common stock, shares issued       16,525,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_SubsidiarySaleOfStockAxis
= us-gaap_IPOMember		  
Underwriters Exercise of Overallotment Option [Member]          
Real Estate Properties [Line Items]          
Common stock, shares issued   2,478,750us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_SubsidiarySaleOfStockAxis
= ahh_UnderwritersExerciseOfOverallotmentOptionMember		      
Operating Partnership [Member]          
Real Estate Properties [Line Items]          
Operating partnership payment of outstanding indebtedness   150.0us-gaap_RepaymentsOfOtherDebt
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		      
Consideration paid to prior investors   $ 47.6us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember		     $ 1.3us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= ahh_OperatingPartnershipMember
Liberty Apartments [Member]          
Real Estate Properties [Line Items]          
Business acquisition date     Jan. 17, 2014