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Business combination fair value adjustment to debt assumed.

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Represents the number of loans assumed in connection with a business combination.

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Business combination, recognized identifiable assets acquired and liabilities assumed, noncurrent liabilities, long-term debt including fair value adjustment.

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Debt Instrument Extension Period

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Debt Service Coverage Ratio

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Defeased debt.

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Line of credit facility covenant compliance leverage ratio.

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Line Of Credit Facility Covenant Compliance Leverage Ratio Consecutive Quarters

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Line Of Credit Facility Covenant Investment To Asset Value

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Line Of Credit Facility Covenant Maximum Number Of Times Leverage Ratio Allowed Increase

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Line of Credit Facility Financial Covenant Percentage of Net Equity Proceeds.

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Line of credit facility covenant secured recourse debt to asset value.

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Line of credit facility covenant, secured recourse indebtedness to asset value.

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Line of credit facility covenant, variable rate indebtedness to asset value

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Line Of Credit Facility Financial Covenant Minimum Tangible Net Worth

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Loan Facility Maximum Commitment Amount

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Percentage Of Adjusted Funds From Operation

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Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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

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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.

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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.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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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.

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The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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The effective interest rate at the end of the reporting period.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

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

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The cash inflow from amounts received from issuance of long-term debt that is wholly or partially secured by collateral. Excludes proceeds from tax exempt secured debt.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Indebtedness - Additional Information (Details)																	12 Months Ended
Indebtedness - Additional Information (Details)	Aug. 30, 2016 USD ($)	Aug. 08, 2016 USD ($)	Oct. 30, 2015 USD ($)	Oct. 06, 2015 USD ($)	Sep. 01, 2015 USD ($)	Jul. 30, 2015 USD ($)	Jul. 10, 2015 USD ($) loan	Jul. 01, 2015 USD ($)	May 27, 2015 USD ($)	May 20, 2015 USD ($)	Nov. 14, 2014 USD ($)	Nov. 03, 2014 USD ($)	Aug. 28, 2014 USD ($)	Aug. 15, 2014 USD ($)	Feb. 28, 2014 USD ($)	Jan. 17, 2014 USD ($)	Dec. 31, 2016 USD ($) leverage_ratio_increase	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Feb. 24, 2017 USD ($)	Feb. 01, 2017 USD ($)	Mar. 31, 2016 USD ($)	Jan. 05, 2016 USD ($)	Feb. 20, 2015 USD ($)	Jun. 13, 2014 USD ($)	Oct. 10, 2013 USD ($)
Debt Instrument [Line Items]
Debt and credit facility repayments, including principal amortization																	$ 186,533,000	$ 206,889,000	$ 63,306,000
Loss on extinguishment of debt																	$ (82,000)	$ (512,000)	$ 0
Liberty Apartments
Debt Instrument [Line Items]
Debt, face value																									$ 2,400,000.0
Debt assumed, term																30 years
Stated interest rate																5.66%
Acquisition, assumption of debt																$ 17,000,000
Fair value adjustment of debt																1,500,000
Outstanding principal amount of debt																$ 18,500,000
Dimmock Square
Debt Instrument [Line Items]
Defeased debt														$ 10,100,000
Smith's Landing
Debt Instrument [Line Items]
Debt, face value									$ 21,600,000.0
Loss on extinguishment of debt									$ (100,000)
Stated interest rate									4.05%								4.05%
Repayment of debt									$ 24,400,000
Socastee Commons
Debt Instrument [Line Items]
Stated interest rate								4.57%									4.57%
Acquisition, assumption of debt								$ 5,000,000
Columbus Village
Debt Instrument [Line Items]
Debt, face value							$ 8,800,000.0
Number of loans assumed \| loan							2
Johns Hopkins Village
Debt Instrument [Line Items]
Debt, face value						$ 50,000,000.0
Oyster Point
Debt Instrument [Line Items]
Repayment of debt					$ 6,100,000
LIBOR \| Columbus Village
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate							2.00%
LIBOR \| Johns Hopkins Village
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate						1.90%											1.90%
LIBOR \| Lightfoot Marketplace
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	1.90%
Minimum \| LIBOR \| Socastee Commons
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	1.35%
Minimum \| LIBOR \| Oyster Point
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	1.40%
Maximum \| LIBOR \| Socastee Commons
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	1.95%
Maximum \| LIBOR \| Oyster Point
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	2.00%
New Retail Mortgage
Debt Instrument [Line Items]
Proceeds from new mortgage		$ 35,000,000
Debt assumed, term		5 years
Loss on extinguishment of debt		$ (100,000)
New Retail Mortgage \| LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate		1.95%
New Block 11 Mortgage
Debt Instrument [Line Items]
Proceeds from new mortgage	$ 57,000,000
Debt assumed, term	5 years
Loss on extinguishment of debt																	$ (100,000)
Stated interest rate	3.25%
Note 4 \| North Point Center
Debt Instrument [Line Items]
Repayment of debt												$ 1,000,000
New Credit Facility
Debt Instrument [Line Items]
Credit facility maximum commitment amount																	$ 250,000,000.0
Unencumbered borrowing base properties, percentage																	60.00%
Debt service coverage ratio																	1.50%
Financial covenant, cash dividend period																	12 months
Percentage of adjusted funds from operations																	95.00%
New Credit Facility \| Subsequent Event
Debt Instrument [Line Items]
Aggregate capacity under the credit facility																					$ 275,000,000.0
Construction Loans
Debt Instrument [Line Items]
Borrowings under construction loans																	$ 44,400,000
Construction Loans \| Whetstone Apartments
Debt Instrument [Line Items]
Loss on extinguishment of debt										$ (100,000)
Repayment of debt										$ 17,800,000
Construction Loans \| Oceaneering
Debt Instrument [Line Items]
Debt, face value															$ 19,500,000.0
Loss on extinguishment of debt			$ (100,000)
Repayment of debt			$ 18,700,000
Construction Loans \| Commonwealth of Virginia
Debt Instrument [Line Items]
Debt, face value													$ 5,400,000.0
Construction Loans \| Lightfoot Marketplace
Debt Instrument [Line Items]
Debt, face value											$ 15,000,000.0
Construction Loans \| Subsequent Event \| Harding Place
Debt Instrument [Line Items]
Debt, face value																				$ 29,800,000
Construction Loans \| LIBOR \| Oceaneering
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate															1.75%
Construction Loans \| LIBOR \| Commonwealth of Virginia
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate													1.90%
Construction Loans \| LIBOR \| Lightfoot Marketplace
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate											1.90%
Revolving Credit Facility
Debt Instrument [Line Items]
Interest rate on credit facility as of end of period (as a percent)																	2.32%
Revolving Credit Facility \| Minimum \| LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	1.40%
Revolving Credit Facility \| Maximum \| LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	2.00%
Revolving Credit Facility \| New Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, extension option																	1 year
Senior Unsecured Term Loan Facility
Debt Instrument [Line Items]
Aggregate capacity under the credit facility																								$ 50,000,000.0
Interest rate on credit facility as of end of period (as a percent)																	2.27%
Senior Unsecured Term Loan Facility \| Minimum \| LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	1.35%
Senior Unsecured Term Loan Facility \| Maximum \| LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate																	1.95%
Senior Unsecured Term Loan Facility \| New Credit Facility \| Subsequent Event
Debt Instrument [Line Items]
Credit facility, amount outstanding																					$ 125,000,000
Operating Partnership \| Oyster Point
Debt Instrument [Line Items]
Debt, face value				$ 6,400,000.0
Operating Partnership \| Minimum \| Oyster Point
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate				1.40%
Operating Partnership \| Maximum \| Oyster Point
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate				2.00%
Operating Partnership \| New Credit Facility
Debt Instrument [Line Items]
Aggregate capacity under the credit facility																								200,000,000.0
Credit facility maximum commitment amount																								350,000,000.0
Financial covenant, minimum tangible net worth amount																	$ 220,000,000.0
Operating Partnership \| New Credit Facility \| Minimum
Debt Instrument [Line Items]
Unused commitment fee																	0.15%
Ratio of adjusted EBITDA to fixed charges																	1.50%
Operating Partnership \| New Credit Facility \| Maximum
Debt Instrument [Line Items]
Unused commitment fee																	0.25%
Financial covenant, maximum leverage ratio as of the last day of each fiscal quarter																	60.00%
Financial covenant, percentage of net equity proceeds																	75.00%
Financial covenant, maximum amount of variable rate indebtedness																	30.00%
Financial covenant, maximum amount of secured recourse indebtedness																	45.00%
Financial covenant, maximum amount of secured recourse debt																	25.00%
Operating Partnership \| Unsecured Debt \| New Credit Facility
Debt Instrument [Line Items]
Aggregate capacity under the credit facility																						$ 250,000,000.0	$ 225,000,000.0
Financial covenant, leverage ratio consecutive quarters following any significant acquisition																	65.00%
Financial covenant, investments to total asset value																	10.00%
Financial covenant, maximum number of times maximum leverage ratio can increase \| leverage_ratio_increase																	2
Operating Partnership \| Revolving Credit Facility
Debt Instrument [Line Items]
Aggregate capacity under the credit facility																										$ 155,000,000.0
Operating Partnership \| Revolving Credit Facility \| New Credit Facility
Debt Instrument [Line Items]
Aggregate capacity under the credit facility																								150,000,000.0
Operating Partnership \| Senior Unsecured Term Loan Facility \| New Credit Facility
Debt Instrument [Line Items]
Aggregate capacity under the credit facility																								$ 50,000,000.0
A249 Central Park Retail
Debt Instrument [Line Items]
Debt and credit facility repayments, including principal amortization		$ 15,100,000
South Retail
Debt Instrument [Line Items]
Debt and credit facility repayments, including principal amortization		6,700,000
Fountain Plaza Retail
Debt Instrument [Line Items]
Debt and credit facility repayments, including principal amortization		$ 7,600,000
A4525 Main Street
Debt Instrument [Line Items]
Debt and credit facility repayments, including principal amortization	$ 31,600,000
Encore Apartments
Debt Instrument [Line Items]
Debt and credit facility repayments, including principal amortization	$ 25,200,000