Acquisition, Development, Construction and Disposition Activity (Details) (USD $)	0 Months Ended	12 Months Ended						3 Months Ended					12 Months Ended	3 Months Ended				12 Months Ended		3 Months Ended		3 Months Ended			12 Months Ended
	Feb. 24, 2014	Dec. 31, 2013 Properties Units		Dec. 31, 2012 Properties		Dec. 31, 2011		Dec. 31, 2013 The Apartments at Blakeney [Member]		Oct. 10, 2013 The Apartments at Blakeney [Member] Units		Dec. 31, 2013 Edge [Member]	Dec. 31, 2013 350 Eighth [Member] Units acre	Dec. 31, 2011 The Brixton [Member]		Oct. 17, 2011 The Brixton [Member] Units		Dec. 31, 2013 NorthwoodRavinPortfolio [Member] Units	Sep. 30, 2013 NorthwoodRavinPortfolio [Member] Properties	Sep. 30, 2011 Dwell Vienna Metro [Member]	Aug. 09, 2011 Dwell Vienna Metro [Member] Units	Jun. 30, 2011 Waterstone at Wellington [Member]	Jun. 15, 2011 Waterstone at Wellington [Member] Units	Dec. 31, 2013 Vista Germantown [Member] Communities	Dec. 31, 2013 GEORGIA Properties	Dec. 31, 2012 GEORGIA Properties	Dec. 31, 2013 OHIO Properties	Dec. 31, 2012 OHIO Properties	Dec. 31, 2011 OHIO Properties	Dec. 31, 2013 FLORIDA Properties	Dec. 31, 2012 MICHIGAN Properties	Dec. 31, 2013 Hancock Real Estate Strategies [Member]	Dec. 31, 2012 Hancock Real Estate Strategies [Member]	Dec. 31, 2013 Future Development [Member] Units		Dec. 31, 2013 Future Development [Member] 350 Eighth [Member] Units		Dec. 31, 2013 Monrovia [Member] Future Development [Member] Units
Business Acquisition [Line Items]
Costs associated with acquisitions		$ 524,000
Number of Real Estate Properties to Acquire																			7
Acquisition cost		80,200,000						53,180,000	[1]				46,600,000	21,000,000	[2]			323,900,000		82,600,000		32,820,000
Assumed loan		28,000,000	[3],[4],[5]	27,589,000	[5]	12,892,000	[5]			28,000,000				12,300,000		12,300,000
Deposits on potential future acquisitions		17,943,000		4,500,000								4,000,000						13,200,000
Lease up period		18 months
Termination Fee		8,000,000
Equity interest																																						50.00%
Apartment units owned		13,676								295	[1]		410			224	[2]	962			250		222	242										626	[6]	410	[6],[7]	154	[6]
Area of land													3.36
Property Dispositions		4		6																					1	1	2	1	2	1	4
Proceeds from sale of property	60,000,000	139,000,000		67,300,000																									30,500,000
Gain on disposition of property	40,000,000.0	52,800,000		26,800,000																									14,600,000
Related party commissions		1,100,000		1,600,000
Related party transaction amount																																$ 130,900,000	$ 104,600,000

[1] Purchase price includes assumed $24.9 million loan, with a fair value of $27.6 million

[2] Purchase price includes assumed $12.3 million loan, with a fair value of $12.9 million

[3] Fair value amount of loan assumed in 2011 at the time of acquisition; actual principal amount of loan assumed was $12.3 million.

[4] Fair value amount of loan assumed in 2012 at the time of acquisition; actual principal amount of loan assumed was

[5] Fair value was equal to principal amount of loan assumed in 2013 at the time of acquisition.

[6] Based on current projections as of February 4, 2014.

[7] On February 3, 2014 we entered into a 50/50 equity joint venture with AIG Global Real Estate to develop and own this property. See Note 19 for additional information.