Real Estate Investments and Equity Method Investments - Other Real Estate Transactions (Details)																		12 Months Ended
	Jan. 10, 2020 USD ($)	Oct. 25, 2019 USD ($)	Oct. 15, 2019	Aug. 15, 2019 USD ($)	Apr. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 20, 2018 USD ($)	Jul. 02, 2018 renewal_term	May 24, 2018 USD ($)	Apr. 02, 2018 USD ($)	Feb. 16, 2018 USD ($)	Jan. 29, 2018 USD ($)	Aug. 10, 2017 USD ($)	Jul. 13, 2017 USD ($) property	Jul. 11, 2017 USD ($)	Jan. 20, 2017 USD ($)	Jan. 04, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 18, 2018
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs																		$ 32,944,000	$ 34,673,000	$ 12,557,000
Charleston, South Carolina
Real Estate [Line Items]
Payments for purchase of land															$ 7,200,000		$ 7,100,000
Capitalized acquisition costs															$ 100,000		$ 200,000
Chesterfield, Virginia
Real Estate [Line Items]
Payments for purchase of land												$ 2,400,000
Capitalized acquisition costs												$ 100,000
Chesterfield, Virginia | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs							$ 25,900,000
Gain (loss) on disposition of property							$ 3,400,000
Broad Creek Shopping Center | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs						$ 2,400,000
Gain (loss) on disposition of property						$ 800,000
Chesapeake And Virginia Beach, Virginia | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Number of properties | property														2
Net proceeds after transaction costs and tax protection payments														$ 7,900,000
Gain (loss) on disposition of property														$ 4,200,000
Sandbridge Commons | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Gain (loss) on disposition of property													$ 500,000
Proceeds from sale of land													$ 300,000
Lightfoot Marketplace | Lightfoot Marketplace | Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs				$ 30,300,000
Gain (loss) on disposition of property				4,500,000
Waynesboro Commons | Waynesboro Commons | Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs					$ 1,100,000
Market At Mill Creek Partners, LLC
Real Estate [Line Items]
Payments for purchase of land											$ 2,900,000
Capitalized acquisition costs											$ 100,000
Percentage of ownership																					70.00%
Brooks Crossing
Real Estate [Line Items]
Payments for purchase of land										$ 100,000
Indian Lakes Crossing | Wawa Outparcel | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs									$ 4,400,000
Gain (loss) on disposition of property									$ 0
Wills Wharf
Real Estate [Line Items]
Lease term								5 years
Number of renewal terms | renewal_term								10
Extension term								7 years
Greentree Shopping Center | Wawa | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Net proceeds after transaction costs and tax protection payments																$ 4,400,000
Gain (loss) on disposition of property																$ 3,400,000
Subsequent Event | Charlotte, NC
Real Estate [Line Items]
Payments for purchase of land	$ 6,300,000
Line of Credit | Secured Debt | Lightfoot Marketplace
Real Estate [Line Items]
Repayment of debt				$ 17,900,000
1023 Roswell, LLC | Primary Beneficiary
Real Estate [Line Items]
Ownership percentage			80.00%
Variable Interest Entity, Funding Commitment		$ 5,000,000.0
1023 Roswell, LLC | Rosewell, Georgia
Real Estate [Line Items]
Payments for purchase of land		$ 5,000,000.0