Represents the optional maximum extension term for ground leases.

No definition available.

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- Definition

Number of ground leases.

+ References

No definition available.

+ Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Term of the lessee's leasing arrangement, 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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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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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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- Definition

Number of separate real estate development properties located on land subject to ground leases.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
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Balance Type:	debit
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- Details

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- Details

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Commitments and Contingencies - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) property lease	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Commitments and Contingencies
Line of credit, performance and payment bonds	$ 40.5	$ 183.0
Number of ground leases \| lease	5
Number of properties subject to ground leases \| property	4
Maximum optional ground lease extension term	40 years
Ground rent expense	$ 2.0	$ 1.7	$ 1.8
Rental Revenues \| Hampton Roads Properties
Commitments and Contingencies
Concentrations of credit risk	52.00%	68.00%	69.00%
Rental Revenues \| Town Center Properties
Commitments and Contingencies
Concentrations of credit risk	41.00%	46.00%	47.00%
Rental Revenues \| Richmond Tower
Commitments and Contingencies
Concentrations of credit risk	1.00%	11.00%	13.00%
General Contracting and Real Estate Services Revenues \| Baltimore
Commitments and Contingencies
Concentrations of credit risk	18.00%	64.00%
General Contracting and Real Estate Services Segment Profit \| Baltimore
Commitments and Contingencies
Concentrations of credit risk	29.00%	50.00%
Minimum
Commitments and Contingencies
Lease term	20 years
Maximum
Commitments and Contingencies
Lease term	65 years
Point Street Apartments \| Financial Guarantee \| Letter of Credit
Commitments and Contingencies
Credit facility, amount outstanding	$ 2.1
Operating Partnership
Commitments and Contingencies
Outstanding letters of credit	$ 4.1	$ 8.0