Investment in Unconsolidated Joint Ventures (Carolina Square Holdings LP) (Details) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) ft² extension apartment_unit	Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items]
Aggregate outstanding indebtedness	$ 342,892	$ 338,590
Carolina Square Holdings LP
Schedule of Equity Method Investments [Line Items]
Ownership percentage of partner in joint venture	50.00%
Number of apartment units | apartment_unit	246
Aggregate outstanding indebtedness	$ 74,638	$ 64,412
Maximum percentage guaranteed under construction loan	12.50%
Cash balance of joint venture	$ 3,800
Carolina Square Holdings LP | LIBOR
Schedule of Equity Method Investments [Line Items]
Basis spread on variable rate (percent)	1.90%
Number of loan extensions | extension	2
Extension period	1 year
Carolina Square Holdings LP | Office Space
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet) | ft²	158
Carolina Square Holdings LP | Retail Space
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet) | ft²	44
Carolina Square Holdings LP | Northwood Ravin
Schedule of Equity Method Investments [Line Items]
Ownership percentage of partner in joint venture	50.00%