Real Estate Investments and Equity Method Investments - Other Real Estate Transactions (Details)																			11 Months Ended	12 Months Ended
	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 ($)	Dec. 22, 2016 USD ($)	Sep. 15, 2016 USD ($)	Jul. 29, 2016 USD ($)	Jun. 20, 2016 USD ($)	Jan. 08, 2016 USD ($)	Jan. 07, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 18, 2018
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs																				$ 34,673,000	$ 12,557,000	$ 96,670,000
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
Economic Development Authority Building | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Net proceeds after transaction costs and tax protection payments																		$ 6,600,000
Gain (loss) on disposition of property																		$ 400,000
Richmond Tower | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Net proceeds after transaction costs and tax protection payments																	$ 77,000,000
Dispositions of real estate investments, net of selling costs																	78,000,000
Gain (loss) on disposition of property																	$ 26,200,000
Willowbrook Commons | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs																$ 9,200,000
Gain (loss) on disposition of property																$ 100,000
Kroger Junction | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs															$ 3,700,000
Gain (loss) on disposition of property															$ (100,000)
Oyster Point | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Net proceeds after transaction costs and tax protection payments														$ 0
Dispositions of real estate investments, net of selling costs														6,400,000
Gain (loss) on disposition of property														$ 3,800,000
Brooks Crossing | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Real Estate [Line Items]
Dispositions of real estate investments, net of selling costs													$ 400,000
Gain (loss) on disposition of property													$ 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
Payments to acquire interest in subsidiaries and affiliates																			$ 21,100,000
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
Charlotte, NC
Real Estate [Line Items]
Purchase of land conjunction with joint venture project																						$ 5,700,000