Business Acquisition, Percentage of Voting Interests Acquired, Option To Purchase Additional Interests

No definition available.

Name:	ahh_BusinessAcquisitionPercentageofVotingInterestsAcquiredOptionToPurchaseAdditionalInterests
Namespace Prefix:	ahh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the company's commitment to invest in a development project, in the form of a loan in which the developer can borrow.

+ References

No definition available.

+ Details

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

- Definition

Represents the extension period of the loan receivable.

+ References

No definition available.

+ Details

Name:	ahh_ExtensionPeriodOfLoanReceivable
Namespace Prefix:	ahh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represent the future value of a real estate development project.

+ References

No definition available.

+ Details

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

- Definition

Represents the percentage of the construction loan the entity has guaranteed.

+ References

No definition available.

+ Details

Name:	ahh_GuaranteePercentageOfConstructionLoan
Namespace Prefix:	ahh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Note Receivable, Face Amount

+ References

No definition available.

+ Details

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

- Definition

Notes Receivable, Interest Reserve

+ References

No definition available.

+ Details

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

- Definition

Represents the number of residential units in a property.

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of rooms in the hotel.

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of stories in the property.

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of times the loan receivable may be extended.

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of assets used as collateral for the construction loan.

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of debt required to be paid.

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the time period after a project's completion date in which the company can exercise the option to purchase an interest in the project.

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Time Period After The Project Completion Date In Which The Company Can Exercise Additional Interests, Purchase Option

+ References

No definition available.

+ Details

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Namespace Prefix:	ahh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the carrying value of a short-term real estate loan to finance building costs. The funds are disbursed as needed or in accordance with a prearranged plan; generally, a portion of the funds is disbursed at inception and the remainder as construction progresses. The money is repaid on completion of the project, usually from the proceeds of a mortgage loan. The rate is normally higher than the prime rate, and there is usually an origination fee. The effective yield on these loans tends to be high, and the lender has a security interest in the real property. Note that there are separate concepts for the current and noncurrent portions of long-term construction loans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20
-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

This item represents disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation; these investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
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-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953401-111524

+ Details

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

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
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-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.12)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 9
-Article 5

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 11
-Article 7

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net amount of nonoperating interest income (expense).

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(3))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash inflow from borrowings to finance the cost of construction.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
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-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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Balance Type:	debit
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- 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

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- Details

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- Details

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- Details

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Real Estate Investments - Unconsolidated Entities (Details) ft² in Thousands			3 Months Ended		6 Months Ended
	Apr. 21, 2016 USD ($) ft² unit room extension	Mar. 16, 2016 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Feb. 25, 2016 story	Dec. 31, 2015 USD ($)	Oct. 31, 2015 USD ($)
Investment in Unconsolidated Subsidiaries
Notes receivable			$ 39,311,000		$ 39,311,000			$ 7,825,000
Interest income			722,000	$ 0	904,000	$ 0
Note receivable, impairment			0		0
SAGH
Investment in Unconsolidated Subsidiaries
Notes receivable			300,000		300,000
Note receivable maximum principal balance		$ 500,000.0
SAGH \| Loans Receivable
Investment in Unconsolidated Subsidiaries
Stated interest rate (as a percent)		10.00%
SAGH \| Loans Receivable \| Period One
Investment in Unconsolidated Subsidiaries
Interest maturity period		120 days
SAGH \| Loans Receivable \| Period Two
Investment in Unconsolidated Subsidiaries
Interest maturity period		3 years
Point Street Apartments
Investment in Unconsolidated Subsidiaries
Commitment to invest in a development project (up to)									$ 23,000,000.0
Notes receivable			15,300,000		15,300,000			$ 7,800,000
Interest income			300,000		400,000
Point Street Apartments \| Loans Receivable
Investment in Unconsolidated Subsidiaries
Note receivable, past due			0		0
Annapolis Junction Town Center
Investment in Unconsolidated Subsidiaries
Notes receivable			23,700,000		23,700,000
Interest income			500,000		500,000
Note receivable maximum principal balance	$ 42,000,000.0
Estimated development project future value	$ 102,000,000
Number of residential units (unit) \| unit	416
Area of retail space (in square feet) \| ft²	17
Number of rooms (room) \| room	150
Interest acquired (as a percent)	80.00%
Period after completion to exercise purchase option (in years)	1 year
Option to acquire additional interest (as a percent)	8.00%
Period after completion to exercise additional purchase option (in months)	27 months
Interest reserve	$ 6,000,000.0
Annapolis Junction Town Center \| Loans Receivable
Investment in Unconsolidated Subsidiaries
Stated interest rate (as a percent)	10.00%
Number of times the loan receivable can be extended (extension) \| extension	2
Extension period of the loan receivable (in years)	1 year
Annapolis Junction Town Center \| Financial Guarantee
Investment in Unconsolidated Subsidiaries
Guarantor obligations, maximum exposure (up to)	$ 25,000,000.0
Annapolis Junction Town Center \| AJAO \| Loans Receivable
Investment in Unconsolidated Subsidiaries
Note receivable, past due			0		0
Required payment of loan (as of a percent)	80.00%
Maximum \| Annapolis Junction Town Center
Investment in Unconsolidated Subsidiaries
Commitment to invest in a development project (up to)	$ 48,000,000.0
Interest acquired (as a percent)	88.00%
Maximum \| Annapolis Junction Town Center \| AJAO
Investment in Unconsolidated Subsidiaries
Senior construction loan (up to)	$ 60,000,000.0
City Center \| 22-Story Mixed Use Tower
Investment in Unconsolidated Subsidiaries
Interests in equity method investments (as a percent)							37.00%
Number stories in the mixed use tower (story) \| story							22
Investment			10,300,000		10,300,000
Guarantee of construction loan (as a percent)							37.00%
Assets being used as collateral for the construction loan (as a percent)							100.00%
Borrowings under construction loans					0
Dividends from equity investment			0		0
Income from equity method investment			$ 0		$ 0