SENIOR NOTES PAYABLE AND OTHER DEBT (Details 2) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2013	$ 36,059,000
2014	825,281,000
2015	983,977,000
2016	844,518,000
2017	1,270,802,000
Thereafter	5,616,140,000
Total	9,576,777,000	9,320,477,000
Unrestricted cash and cash equivalents	86,635,000	94,816,000	62,421,000	67,908,000	62,421,000
Unsecured revolving credit facilities
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total	179,373,000	376,343,000
Amount outstanding, net of cash and cash equivalents	92,700,000
Mortgage loans and other
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total	2,278,686,000	2,524,889,000
6.90% Senior Notes due 2037
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total	52,400,000	52,400,000
Interest rate (as a percent)	6.90%	6.90%
6.59% Senior Notes due 2038
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total	22,973,000	22,973,000
Interest rate (as a percent)	6.59%	6.59%
Principal Amount Due at Maturity
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2013	15,176,000
2014	786,891,000
2015	950,020,000
2016	821,947,000
2017	1,075,209,000
Thereafter	5,466,151,000
Total	9,115,394,000
Unsecured Revolving Credit Facility
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2013	0
2014	0
2015	0
2016	0
2017	179,373,000
Thereafter	0
Total	179,373,000
Scheduled Periodic Amortization
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2013	20,883,000
2014	38,390,000
2015	33,957,000
2016	22,571,000
2017	16,220,000
Thereafter	149,989,000
Total	$ 282,010,000