Mortgage and Other Indebtedness (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended					1 Months Ended	12 Months Ended		12 Months Ended					3 Months Ended					12 Months Ended																										3 Months Ended																		12 Months Ended																		3 Months Ended				3 Months Ended									3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended															1 Months Ended
	Mar. 31, 2011 Loans	Dec. 31, 2011		Dec. 31, 2010		Jan. 30, 2012 Repayment of Debt [Member] Loans	Dec. 31, 2011 Minimum [Member] Extension_Options	Sep. 30, 2011 Minimum [Member]	Dec. 31, 2011 Maximum [Member]	Dec. 31, 2011 Interest Rate Swap [Member]	Mar. 31, 2011 Interest Rate Swap [Member]	Dec. 31, 2011 Secured Line of Credit Two, Reduced Capacity [Member]		Dec. 31, 2011 Secured Line of Credit 3 [Member]		Dec. 31, 2011 Secured Line of Credit 1 [Member]	Dec. 31, 2011 Letter of Credit 1 [Member]	Dec. 31, 2011 Letter of Credit 2 [Member]	Dec. 31, 2011 Unsecured Term Loan 2 [Member]	Dec. 31, 2011 Fixed Rate Interest [Member]		Dec. 31, 2010 Fixed Rate Interest [Member]		Dec. 31, 2011 Variable Rate Interest Member [Member]		Dec. 31, 2010 Variable Rate Interest Member [Member]		Dec. 31, 2011 Non-recourse Loans on Operating Properties [Member]		Mar. 31, 2011 Non-recourse Loans on Operating Properties [Member]	Dec. 31, 2010 Non-recourse Loans on Operating Properties [Member]		Dec. 31, 2011 Non-recourse Loans on Operating Properties [Member] Fixed Rate Interest [Member]		Dec. 31, 2010 Non-recourse Loans on Operating Properties [Member] Fixed Rate Interest [Member]		Dec. 31, 2011 Non-recourse Loans on Operating Properties [Member] Variable Rate Interest Member [Member]		Dec. 31, 2010 Non-recourse Loans on Operating Properties [Member] Variable Rate Interest Member [Member]		Dec. 31, 2011 Recourse Term Loans on Operating Properties [Member]		Dec. 31, 2010 Recourse Term Loans on Operating Properties [Member]		Dec. 31, 2011 Recourse Term Loans on Operating Properties [Member] The Promenade at Dlberville [Member]	Mar. 31, 2011 Recourse Term Loans on Operating Properties [Member] The Promenade at Dlberville [Member] Extension_Options	Dec. 31, 2011 Recourse Term Loans on Operating Properties [Member] Hammock Landing Phase II [Member]	Mar. 31, 2011 Recourse Term Loans on Operating Properties [Member] Hammock Landing Phase II [Member]	Dec. 31, 2011 Recourse Term Loans on Operating Properties [Member] Fixed Rate Interest [Member]		Dec. 31, 2010 Recourse Term Loans on Operating Properties [Member] Fixed Rate Interest [Member]		Dec. 31, 2011 Recourse Term Loans on Operating Properties [Member] Variable Rate Interest Member [Member]		Dec. 31, 2010 Recourse Term Loans on Operating Properties [Member] Variable Rate Interest Member [Member]		Dec. 31, 2011 Construction Loans [Member]	Dec. 31, 2010 Construction Loans [Member]	Dec. 31, 2011 Construction Loans [Member] Variable Rate Interest Member [Member]		Dec. 31, 2010 Construction Loans [Member] Variable Rate Interest Member [Member]		Dec. 31, 2011 Secured Lines of Credit [Member] Properties CreditLines	Dec. 31, 2010 Secured Lines of Credit [Member]	Dec. 31, 2011 Secured Lines of Credit [Member] Variable Rate Interest Member [Member]		Dec. 31, 2010 Secured Lines of Credit [Member] Variable Rate Interest Member [Member]		Dec. 31, 2011 Unsecured Term Loans [Member] CreditLines	Dec. 31, 2010 Unsecured Term Loans [Member]	Dec. 31, 2011 Unsecured Term Loans [Member] Unsecured Term Loan 1 [Member]	Dec. 31, 2011 Unsecured Term Loans [Member] Unsecured Term Loan 1 [Member] Minimum [Member]	Dec. 31, 2011 Unsecured Term Loans [Member] Unsecured Term Loan 1 [Member] Maximum [Member]	Dec. 31, 2011 Unsecured Term Loans [Member] Unsecured Term Loan 2 [Member]	Dec. 31, 2011 Unsecured Term Loans [Member] Unsecured Term Loan 2 [Member] Minimum [Member]	Dec. 31, 2011 Unsecured Term Loans [Member] Unsecured Term Loan 2 [Member] Maximum [Member]	Dec. 31, 2011 Unsecured Term Loans [Member] Variable Rate Interest Member [Member]		Dec. 31, 2010 Unsecured Term Loans [Member] Variable Rate Interest Member [Member]		Sep. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Loans	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Loans	Mar. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] Park Plaza Mall [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Park Plaza Mall [Member]	Dec. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] Cross Creek Mall [Member]	Dec. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] Outlet Shoppes at Oklahoma City [Member]	Sep. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Alamance Crossing [Member]	Sep. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Asheville Mall [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Fayette Mall [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Mid Rivers Mall [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Panama City Mall [Member]	Mar. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] Parkdale Mall and Parkdale Crossing [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Parkdale Mall and Parkdale Crossing [Member]	Mar. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] Eastgate Mall [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Eastgate Mall [Member]	Mar. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] Wasau Center [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Wasau Center [Member]	Mar. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] Hamilton Crossing [Member]	Jun. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] Hamilton Crossing [Member]	Dec. 31, 2011 Non Recourse Term Loans On Operating Properties [Member] St. Clair Square [Member]	Sep. 30, 2011 Non Recourse Term Loans On Operating Properties [Member] St. Clair Square [Member]	Dec. 31, 2011 Recourse and Nonrecourse Term Loans Member [Member]	Mar. 31, 2011 Recourse and Nonrecourse Term Loans Member [Member]	Dec. 31, 2011 Partial Recourse Loans On Operating Properties [Member]	Mar. 31, 2011 Partial Recourse Loans On Operating Properties [Member]	Mar. 31, 2011 Partial Recourse Loans On Operating Properties [Member] Stroud Mall [Member]	Mar. 31, 2011 Partial Recourse Loans On Operating Properties [Member] York Galleria [Member]	Mar. 31, 2011 Partial Recourse Loans On Operating Properties [Member] Gunbarrel Pointe [Member]	Mar. 31, 2011 Partial Recourse Loans On Operating Properties [Member] Coolsprings Crossing [Member]	Dec. 31, 2011 Fixed Rate Operating Loans [Member] Y	Dec. 31, 2011 Fixed Rate Operating Loans [Member] Minimum [Member]	Dec. 31, 2011 Fixed Rate Operating Loans [Member] Maximum [Member]	Dec. 31, 2011 Variable Rate Debt [Member] Minimum [Member] Y	Dec. 31, 2011 Variable Rate Debt [Member] Maximum [Member]	Oct. 31, 2011 Secured Debt [Member] Pearland Town Center [Member]	Oct. 31, 2011 Secured Debt [Member] West County Center [Member]
Debt Instrument [Line Items]
Mortgage and other indebtedness, fixed rate		$ 3,733,355		$ 3,694,742																								$ 3,656,243	[1]		$ 3,664,293	[1]									$ 77,112	[1]	$ 30,449	[1]
Mortgage and other indebtedness, variable-rate debt		756,000		1,515,005																								168,750			114,625										124,439		350,106														25,921	14,536					27,300	598,244					409,590	437,494	181,590			228,000
Mortgage and other indebtedness		4,489,355		5,209,747
Weighted Average Interest Rate		4.99%	[2]	4.92%	[2]						4.57%									5.54%	[2]	5.85%	[2]	2.18%	[2]	2.65%	[2]	5.64%	[1],[2]				5.55%	[1],[2]	5.85%	[1],[2]	3.03%	[2]	3.61%	[2]									5.89%	[1],[2]	6.00%	[1],[2]	2.29%	[2]	2.28%	[2]			3.25%	[2]	3.32%	[2]			3.03%	[2]	3.38%	[2]									1.67%	[2]	1.66%	[2]																								4.57%
Number of instruments held										4	4
Notional amount of interest rate swaps held										117,700	120,165
Secured non-recourse and recourse term loans																																																																																																						4,784,116
Line of Credit Facility [Abstract]
Number of secured lines of credit																																																															3						2
Basis spread on variable rate							2.00%	1.50%	3.00%																																				1.75%		2.00%																									0.95%	1.40%		1.50%	1.80%																								3.00%		2.40%
Decrease in basis spread														(2.75%)		(2.50%)
Weighted-average interest rate																			1.88%																																												3.03%								1.40%
Line of credit facility, commitment fee percentage							0.15%		0.35%
Secured credit facility, borrowing capacity		1,150,000										105,000	[3]	525,000	[2]	520,000
Secured credit facility, amount outstanding		27,300										15,000		0	[2]	12,300
Amount outstanding on letter of credit														4,870				2,915
Line of credit facility, capacity available for specific purpose																	50,000	16,021
Retirement of term loan																																																																																					56,823	39,274	51,847	61,346	84,733	74,748	36,317																								133,884	20,786
Number of properties collateralizing loans																																																															31
Carrying value of assets pledged as collateral																																																															741,391
Mortgage loans closed	5																																																																																2	2
Fixed interest, percentage rate																																																																																					4.54%	5.73%	5.83%	5.80%	5.42%	5.88%																					4.54%	8.50%
Unamortized premium		291																																																																																																												291
Weighted average maturity (Years)																																																																																																														4.68			2.69
Debt instrument, face amount																														268,905																58,000		3,300																																	128,800	277,000		99,400	140,000	60,000	50,800	78,000	185,000	92,000			95,000		44,100		19,800		10,605				120,165		7,540	36,365	58,100	12,100	13,600
Number of operating property loans						10
Fixed rate debt, maturity (years)																																																																																			10 years		10 years	10 years	10 years	10 years	10 years	10 years		10 years		10 years		10 years		10 years
Variable interest, percentage rate																																																																																																																	1.30%	4.50%
Non-recourse debt																																																																																																				$ 125,000	$ 69,375
Number of one-year extension options available							1																																							2
Option to extend recourse loan terms, in years							1 year		2 years										1 year																										2 years																																																							5 years
Debt instrument, percentage of reference rate added to basis points																																													75.00%
Variable rate debt, maturity period																																													3 years

[1] The Company had four interest rate swaps on notional amounts totaling $117,700 as of December 31, 2011 related to its variable-rate loans on operating Properties to effectively fix the interest rates on the respective loans. Therefore, these amounts are reflected in fixed-rate debt in 2011.

[2] Weighted-average interest rate includes the effect of debt premiums (discounts), but excludes amortization of deferred financing costs.

[3] There was an additional $4,870 outstanding on this secured line of credit as of December 31, 2011 forletters of credit. Up to $50,000 of the capacity on this line can be used for letters of credit.