Mortgage and Other Indebtedness (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended		0 Months Ended		9 Months Ended		9 Months Ended	6 Months Ended	9 Months Ended	3 Months Ended	6 Months Ended	9 Months Ended	6 Months Ended		9 Months Ended							3 Months Ended					3 Months Ended
	Sep. 30, 2011 Years	Jun. 30, 2011	Mar. 31, 2011 Years Loans Swap_Agreements	Sep. 30, 2011 Years	Dec. 31, 2010 Years	Oct. 05, 2011 Repayment of Debt [Member] Loan Secured by Pearland Town Center [Member]	Oct. 05, 2011 Repayment of Debt [Member] Loan Secured by West County Center [Member]	Sep. 30, 2011 Unsecured lines of credit [Member]	Sep. 30, 2011 Unsecured lines of credit [Member] Starmount [Member]	Sep. 30, 2011 Unsecured Line of Credit 2 [Member]	Sep. 30, 2011 Secured Line of Credit 1 [Member]	Sep. 30, 2011 Secured Line of Credit 1 [Member]	Jun. 30, 2011 Secured Line of Credit 2 [Member]	Sep. 30, 2011 Secured Line of Credit 2 [Member]	Sep. 30, 2011 Secured Line of Credit 2 [Member]	Sep. 30, 2011 Secured Line of Credit 3 [Member]		Sep. 30, 2011 Secured Line of Credit 3 [Member]		Sep. 30, 2011 Secured Line of Credit Two, Reduced Capacity [Member]	Sep. 30, 2011 Letter of Credit [Member]	Sep. 30, 2011 Secured Debt [Member] CreditLines	Sep. 30, 2011 Unsecured Debt [Member] CreditLines	Sep. 30, 2011 Unsecured Debt [Member] Starmount [Member]	Sep. 30, 2011 Non Recourse Loans On Operating Properties [Member] Loans	Jun. 30, 2011 Non Recourse Loans On Operating Properties [Member] Loans	Mar. 31, 2011 Non Recourse Loans On Operating Properties [Member] Loans	Mar. 31, 2011 Partial Recourse Loans On Operating Properties [Member] Loans	Sep. 30, 2011 Operating Property Loan [Member]	Sep. 30, 2011 Loan Secured by Alamance Crossing [Member]	Sep. 30, 2011 Loan Secured by Asheville Mall [Member]	Jun. 30, 2011 Loan Secured by Fayette Mall [Member]	Jun. 30, 2011 Loan Secured by Mid Rivers Mall [Member]	Sep. 30, 2011 Existing Loan, One [Member]	Jun. 30, 2011 Existing Loan, One [Member]	Sep. 30, 2011 Existing Loan, Two [Member]	Jun. 30, 2011 Existing Loan, Two [Member]	Jun. 30, 2011 Loan Secured by Panama City Mall [Member]	Mar. 31, 2011 Loan Secured by Parkdale Mall and Parkdale Crossing [Member]	Mar. 31, 2011 Loan Secured by Park Plaza [Member]	Mar. 31, 2011 Loan Secured by EastGate Mall [Member]	Mar. 31, 2011 Loan Secured by Wausau Center [Member]	Mar. 31, 2011 Loan Secured by Hamilton Crossing [Member]	Mar. 31, 2011 Loan Secured by Stroud Mall [Member]	Mar. 31, 2011 Loan Secured by York Galleria [Member]	Mar. 31, 2011 Loan Secured by Gunbarrel Pointe [Member]	Mar. 31, 2011 Loan Secured by CoolSprings Crossing [Member]
Lines of Credit [Abstract]
Interest rate terms								LIBOR plus a margin ranging from 0.95% to 1.40%		LIBOR plus a margin ranging from 1.50% to 1.80%		LIBOR plus an applicable spread, ranging from 2.00% to 3.00%																LIBOR plus a margin of 2.40%
Weighted average interest rate (in hundredths)	2.99%			2.99%				1.34%		1.83%
Lines of Credit, Number																						3	2
Interest Rate, Decrease											2.75%		2.50%	2.50%		2.75%
Number of one-year extension options available								1
Fees on amount of unused availability of secured lines of credit, minimum (in hundredths)				0.15%
Fees on amount of unused availability of secured lines of credit, maximum (in hundredths)				0.35%
Percentage floor on LIBOR removed	1.50%
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,145,084			$ 1,145,084						$ 228,000	$ 520,000	$ 520,000		$ 105,000	$ 105,000	$ 525,000	[1]	$ 525,000	[1]	$ 100,084	$ 50,000
Line of Credit Facility, Amount Outstanding								209,214	209,214		150,196	150,196		17,700	17,700	47,130	[1]	47,130	[1]
Line of credit maturity date								Nov. 30, 2011				Apr. 28, 2014			Jun. 01, 2013			Feb. 26, 2014	[1]
Line of credit, extended maturity date								Nov. 30, 2012										Feb. 26, 2015	[1]
Additional amount outstanding for letter of credit	12,045			12,045												4,870		4,870
Additional secured and unsecured lines of credit with commitment	16,021			16,021
Covenants and Restrictions [Abstract]
Minimum loan amount in default payment for recourse loan	50,000			50,000
Minimum loan amount in default payment for non-recourse loan	100,000			100,000
Mortgages on Operating Properties [Abstract]
Mortgage loans closed			9																						2	2	5	4
Nonrecourse mortgage loans closed , amount	128,800	277,000	268,905																											50,800	78,000	185,000	92,000						95,000	99,400	44,100	19,800	10,605	36,365	58,100	12,100	13,600
Nonrecourse mortgage loans closed , terms (in years)	10	10	10
Interest rate on mortgage loan (in hundredths)																														5.83%	5.80%	5.42%	5.88%
Partial-recourse Mortgage [Abstract]
Partial-recourse in loans			13,998
Interest rate terms								LIBOR plus a margin ranging from 0.95% to 1.40%		LIBOR plus a margin ranging from 1.50% to 1.80%		LIBOR plus an applicable spread, ranging from 2.00% to 3.00%																LIBOR plus a margin of 2.40%
Partial-recourse Mortgage Loan, Term			5
Expected reduction in partial-recourse			5,650
Numbers of loans secured with properties previously used as collateral to secure the $520,000 credit facility			8
Weighted Average Interest Rate On Mortgage And Other Indebtedness																											5.64%	4.57%
Interest Rate Hedge Instruments [Abstract]
Number of pay fixed/receive variable interest rate swaps company entered into			4
Interest rate derivatives, notional amount			120,165
Pay fixed/receive, variable interest rate swaps, amortized amount			100,009
Swap Maturity date								Nov. 30, 2011				Apr. 28, 2014			Jun. 01, 2013			Feb. 26, 2014	[1]
Schedule of principal repayments [Abstract]
2011	364,708			364,708																				209,214					133,834
2012	991,651			991,651
2013	554,866			554,866
2014	409,744			409,744
2015	813,499			813,499
Thereafter	2,098,321			2,098,321
Total payments	5,232,789			5,232,789
Net unamortized premiums	359			359
Total payments, net of unamortized premiums	5,233,148			5,233,148	5,209,747
Scheduled principal payments	364,708			364,708																				209,214					133,834
Repayment of existing loans						$ 133,884	$ 20,786																											$ 51,847	$ 84,733	$ 61,346	$ 74,748	$ 36,317
Weighted average maturity of mortgage and other indebtedness (in years)	4.1			4.1	3.5

[1] There was an additional $4,870 outstanding on this secured line of credit as of September 30, 2011 for letters of credit. Up to $50,000 of the capacity on this line can be used for letters of credit.