Real Estate Investments and Equity Method Investments - Schedule of Real Estate Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Real Estate Properties [Line Items]
Land	$ 280,791	$ 275,523
Land improvements	61,275	58,636
Buildings and improvements	1,357,684	1,138,829
Development and construction costs	58,167	133,336
Real estate investments	1,757,917	1,606,324	$ 1,176,586
Income producing property
Real Estate Properties [Line Items]
Land	261,984	263,258
Land improvements	61,275	58,636
Buildings and improvements	1,357,684	1,138,829
Development and construction costs	0	0
Real estate investments	1,680,943	1,460,723
Held for development
Real Estate Properties [Line Items]
Land	13,607	5,000
Land improvements	0	0
Buildings and improvements	0	0
Development and construction costs	0	0
Real estate investments	13,607	5,000
Construction in progress
Real Estate Properties [Line Items]
Land	5,200	7,265
Land improvements	0	0
Buildings and improvements	0	0
Development and construction costs	58,167	133,336
Real estate investments	$ 63,367	$ 140,601

Capitalized development and construction costs.

No definition available.

Name:	ahh_DevelopmentAndConstructionCosts
Namespace Prefix:	ahh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of real estate investment property, excluding real estate investments held for sale.

+ References

No definition available.

+ Details

Name:	ahh_RealEstateInvestmentPropertyAtCostExcludingRealEstateHeldForSale
Namespace Prefix:	ahh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 4
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=121566466&loc=d3e6812-107765

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

Name:	us-gaap_BuildingsAndImprovementsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.13)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 4
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121566466&loc=d3e6812-107765

+ Details

Name:	us-gaap_Land
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before accumulated deprecation and depletion of additions or improvements to real estate held for productive use. Examples include, but are not limited to, walkways, driveways, fences, and parking lots.

+ References

No definition available.

+ Details

Name:	us-gaap_LandImprovements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=ahh_IncomeProducingPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=ahh_HeldForDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ConstructionInProgressMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: