Real Estate Acquisitions and Dispositions Real Estate Acquisitions and Dispositions - Additional Information (Details)	Dec. 31, 2015 ft² a Apartments
Colonial Promenade Craft Farms
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	67,735
Area of Land | a	0.23
River's Walk [Member]
Significant Acquisitions and Disposals [Line Items]
Area of Land | a	2.5
Residences at Burlington Creek [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	298
SkySong [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	325
Retreat at West Creek [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	254
Radius [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	252
Haven at Prairie Trace [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	280
Retreat at West Creek II [Member]
Significant Acquisitions and Disposals [Line Items]
Area of Land | a	4.4
Cityscape at Market Center II [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	318
Vistas
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	144
Fountain Lake [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	113
Westbury Creek [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	120
Woodwinds [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	144
Colony at South Park [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	184
Bradford Pointe [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	192
Anatole [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	208
Oaks, The
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	100
The Denton [Member]
Significant Acquisitions and Disposals [Line Items]
Number of units in real estate property	55
The Denton II [Member]
Significant Acquisitions and Disposals [Line Items]
Area of Land | a	4.51
Austin Chase
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	256
Fairways at Heartland [Member]
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	240
Post House Jackson
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	150
Woods of Post House
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	122
Post House North
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	145
Bradford Chase
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	148
Sutton Place [Member]
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	253
Southland Station [Member]
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	304
Huntington Chase [Member]
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	200
Paddock Park Ocala
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	480
Colonial Grand at Wilmington [Member]
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	390
Savannah Creek [Member]
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	204
Whisperwood [Member]
Significant Acquisitions and Disposals [Line Items]
Square footage of real estate property (square foot) | ft²	1,008