Real Estate Investments and Equity Method Investments - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Real Estate Properties [Line Items]
Land	$ 98,186
Site improvements	7,742
Building and improvements	136,769
In-place leases	31,993
Above-market leases	2,250
Below-market leases	(13,579)
Net assets acquired	263,361
11- asset retail portfolio
Real Estate Properties [Line Items]
Land	66,260
Site improvements	3,870
Building and improvements	88,820
In-place leases	20,630
Above-market leases	1,960
Below-market leases	(11,040)
Net assets acquired	170,500
Southgate Square
Real Estate Properties [Line Items]
Land	8,890
Site improvements	2,140
Building and improvements	23,810
In-place leases	5,990
Above-market leases	100
Below-market leases	(1,400)
Net assets acquired	39,530
Southshore Shops
Real Estate Properties [Line Items]
Land	1,770
Site improvements	490
Building and improvements	6,019
In-place leases	1,140
Above-market leases	120
Below-market leases	(190)
Net assets acquired	9,349
Columbus Village II
Real Estate Properties [Line Items]
Land	14,536
Site improvements	939
Building and improvements	9,983
In-place leases	2,225
Above-market leases	0
Below-market leases	(939)
Net assets acquired	26,744
Renaissance Square
Real Estate Properties [Line Items]
Land	6,730
Site improvements	303
Building and improvements	8,137
In-place leases	2,008
Above-market leases	70
Below-market leases	(10)
Net assets acquired	$ 17,238
2015 Operating Property Acquisitions
Real Estate Properties [Line Items]
Land		$ 29,500
Site improvements		3,290
Building and improvements		49,260
In-place leases		14,160
Above-market leases		2,260
Below-market leases		(4,420)
Indebtedness		(13,935)
Net assets acquired		$ 80,115