SENIOR NOTES PAYABLE AND OTHER DEBT (Details 2) (USD $)					6 Months Ended				1 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2013 Unsecured revolving credit facilities	Dec. 31, 2012 Unsecured revolving credit facilities	Jun. 30, 2013 Mortgage loans and other	Dec. 31, 2012 Mortgage loans and other	Jul. 25, 2013 Mortgage loans and other Subsequent Event	Jun. 30, 2013 6.90% Senior Notes due 2037	Dec. 31, 2012 6.90% Senior Notes due 2037	Jun. 30, 2013 6.59% Senior Notes due 2038	Dec. 31, 2012 6.59% Senior Notes due 2038	Jun. 30, 2013 Principal Amount Due at Maturity	Jun. 30, 2013 Unsecured Revolving Credit Facility	Jun. 30, 2013 Scheduled Periodic Amortization
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2013	$ 211,249,000													$ 184,866,000	$ 0	$ 26,383,000
2014	342,941,000													294,206,000	0	48,735,000
2015	1,353,152,000													1,053,864,000	259,616,000	39,672,000
2016	443,458,000													410,917,000	0	32,541,000
2017	943,106,000													922,715,000	0	20,391,000
Thereafter	5,068,803,000													4,910,132,000	0	158,671,000
Total	8,362,709,000	8,186,315,000			259,616,000	540,727,000	2,856,244,000	2,880,609,000		52,400,000	52,400,000	22,973,000	22,973,000	7,776,700,000	259,616,000	326,393,000
Interest rate (as a percent)										6.90%	6.90%	6.59%	6.59%
Unrestricted cash and cash equivalents	62,421,000	67,908,000	52,803,000	45,807,000
Amount outstanding, net of cash and cash equivalents					197,200,000
Line of credit facility optional extension period					1 year
Repayments of long-term debt due in 2013									108,100,000
Repayments of long-term debt due in 2014									$ 18,100,000