Undeveloped Land and Construction in Progress (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011	Jun. 30, 2012		Jun. 30, 2011
Undeveloped Land and Construction in Progress
Number of active development projects				8
Future undeveloped land and construction in progress	$ 207,529,000			$ 207,529,000
Undeveloped land and construction in progress	340,530,000			340,530,000
Capitalized interest	400,000		100,000	500,000		100,000
Multifamily
Undeveloped Land and Construction in Progress
Developments initiated in current period	2
For-Sale Residential Land
Undeveloped Land and Construction in Progress
Impairment of real estate				24,600,000
Active Development
Undeveloped Land and Construction in Progress
Cost capitalized to date	133,001,000			133,001,000
Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	129,237,000			129,237,000
Total units	2,018	[1]		2,018	[1]
Future Development
Undeveloped Land and Construction in Progress
Undeveloped land	132,000,000			132,000,000
Future Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	29,665,000			29,665,000
Undeveloped land	2,341,000			2,341,000
Total units	1,049	[1]		1,049	[1]
Future Development | Commercial Real Estate
Undeveloped Land and Construction in Progress
Cost capitalized to date	45,864,000			45,864,000
Undeveloped land	45,338,000			45,338,000
Total square feet				236,000	[1]
Future Development | Commercial Outparcels/Pads
Undeveloped Land and Construction in Progress
Undeveloped land	14,397,000			14,397,000
Future Development | For-Sale Residential Land
Undeveloped Land and Construction in Progress
Undeveloped land	69,924,000	[2]		69,924,000	[2]
Colonial Grand at Ayrsley Phase II (Charlotte, NC) | Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	1,484,000			1,484,000
Total units	81	[1]		81	[1]
Colonial Grand at Double Creek (Austin, TX) | Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	15,972,000			15,972,000
Total units	296	[1]		296	[1]
Colonial Grand at Hampton Preserve (Tampa, FL) | Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	51,033,000			51,033,000
Total units	486	[1]		486	[1]
Colonial Grand at Lake Mary Phase I (Orlando, FL) | Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	21,565,000			21,565,000
Total units	232	[1]		232	[1]
Colonial Grand at Lake Mary Phase II (Orlando, FL) | Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	4,394,000			4,394,000
Total units	108	[1]		108	[1]
Colonial Grand at Randal Park (Orlando, FL) | Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	16,062,000			16,062,000
Total units	462	[1]		462	[1]
Colonial Reserve at South End (Charlotte, NC) | Active Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	18,727,000			18,727,000
Total units	353	[1]		353	[1]
Colonial Promenade Huntsville Phase I (Huntsville, AL) | Active Development | Commercial Real Estate
Undeveloped Land and Construction in Progress
Cost capitalized to date	3,764,000	[3]		3,764,000	[3]
Total square feet
Colonial Grand at Azure (Las Vegas, NV) | Future Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	10,575,000			10,575,000
Total units	390	[1]		390	[1]
Colonial Grand at Bellevue Phase II (Nashville, TN) | Future Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	3,441,000			3,441,000
Total units	220	[1]		220	[1]
Colonial Grand at Sweetwater (Phoenix, AZ) | Future Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	7,240,000			7,240,000
Total units	195	[1]		195	[1]
Colonial Grand at Thunderbird (Phoenix, AZ) | Future Development | Multifamily
Undeveloped Land and Construction in Progress
Cost capitalized to date	8,409,000			8,409,000
Total units	244	[1]		244	[1]
Colonial Promenade Huntsville Phase II (Huntsville, AL) | Future Development | Commercial Real Estate
Undeveloped Land and Construction in Progress
Cost capitalized to date	3,958,000	[3]		3,958,000	[3]
Total square feet
Colonial Promenade Nord du Lac (Covington, LA)
Undeveloped Land and Construction in Progress
Impairment of real estate				25,800,000
Colonial Promenade Nord du Lac (Covington, LA) | Future Development | Commercial Real Estate
Undeveloped Land and Construction in Progress
Cost capitalized to date	25,311,000	[4]		25,311,000	[4]
Total square feet				236,000	[1],[4]
Randal Park | Future Development | Commercial Real Estate
Undeveloped Land and Construction in Progress
Cost capitalized to date	$ 16,595,000			$ 16,595,000
Total square feet

[1] Units refer to multifamily apartment units. Square feet refers to commercial space and excludes space owned by anchor tenants.

[2] These costs are presented net of $24.6 million of non-cash impairment charges recorded on two of the projects in 2009, 2008 and 2007.

[3] The Company is currently preparing site-work for this commercial development. The Company is still evaluating plans for this commercial project. Therefore, dollars attributable to this development are subject to change.

[4] The Company intends to develop this project in phases over time. Costs capitalized to date for this development, including costs for Phase I, which was placed into service in 2010, are presented net of an aggregate of $25.8 million of non-cash impairment charges recorded during 2009 and 2008.