Mortgages on Operating Properties (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended			3 Months Ended		6 Months Ended	3 Months Ended													3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012	Jun. 30, 2012	Dec. 31, 2011	Mar. 31, 2012 Northwoods Mall [Member]	Jun. 30, 2012 Statesboro Crossing [Member]	Jun. 30, 2012 Columbia Place [Member]	Jun. 30, 2012 Arbor Place [Member]	Mar. 31, 2012 Arbor Place [Member]	Jun. 30, 2012 Jefferson Mall [Member]	Mar. 31, 2012 Jefferson Mall [Member]	Jun. 30, 2012 Southpark Mall [Member]	Jun. 30, 2012 Fashion Square [Member]	Mar. 31, 2012 Fashion Square [Member]	Jun. 30, 2012 Westgate Mall [Member]	Jun. 30, 2012 CBL Center [Member]	Jun. 30, 2012 CBL Center II [Member]	Jun. 30, 2012 CBL Center I and II [Member]	Jun. 30, 2012 Construction Loans [Member]	Jun. 30, 2012 Operating Property Loan [Member]	Jun. 30, 2012 Statesboro Crossing [Member]	Mar. 31, 2012 Statesboro Crossing [Member]
Mortgages on Operating Properties [Abstract]
Mortgage Loans on Real Estate, New Mortgage Loans					$ 73,000			$ 122,000		$ 71,190		$ 67,000	$ 42,000		$ 40,000			$ 22,000
Nonrecourse mortgage loans closed , terms (in years)					10 years			10 years		10 years		10 years			10 years			10 years
Interest rate on mortgage loan (in hundredths)					5.075%				5.099%		4.75%	4.845%		4.95%	4.99%			5.00%
Debt Instrument, Description of Variable Rate Basis						one-month LIBOR plus a spread of 1%
Number of Debt Instruments Retired	15
Extinguishment of Debt, Amount	394,386											30,763				12,818	9,078
Debt Instrument, Maturity Date						Feb. 15, 2013	Sep. 01, 2013
Debt Instrument Maximum Borrowing Capacity																					13,568	20,911
Weighted average maturity of mortgage and other indebtedness (in years)			5.09	4.69
Mortgage Loans on Real Estate, Carrying Amount of Mortgages							27,265												2,023	122,169
Schedule of principal repayments [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months			330,037
2013			624,781
2014			329,072
2015			482,436
2016			778,893
Thereafter			2,138,305
Total payments			4,683,524
Net unamortized premiums			9,684
Mortgage and other indebtedness			4,693,208	4,489,355
Mortgage Loans on Real Estate, Number of Loans		2
Mortgage Loans on Real Estate, Carrying Amount of Mortgages							27,265												2,023	122,169
Line of Credit Facility, Amount Outstanding			167,209
Mortgage Loans on Real Estate Payment of Monthly Principal Amortization			38,636
Debt maturing in current year with extension available																				77,500
Debt Maturing In Current Year Without Extension Options Available			$ 211,878