SENIOR NOTES PAYABLE AND OTHER DEBT (Details 2) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2013	$ 96,831,000
2014	959,189,000
2015	994,625,000
2016	562,036,000
2017	1,657,242,000
Thereafter	5,172,713,000
Total	9,442,636,000	9,320,477,000
Unrestricted cash and cash equivalents	59,791,000	94,816,000	57,690,000	67,908,000	57,690,000
Unsecured revolving credit facilities
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total	559,299,000	376,343,000
Amount outstanding, net of cash and cash equivalents	499,500,000
Mortgage loans and other
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total	2,468,629,000	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	62,634,000
2014	918,459,000
2015	960,917,000
2016	540,072,000
2017	1,082,497,000
Thereafter	5,025,751,000
Total	8,590,330,000
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	559,299,000
Thereafter	0
Total	559,299,000
Scheduled Periodic Amortization
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2013	34,197,000
2014	40,730,000
2015	33,708,000
2016	21,964,000
2017	15,446,000
Thereafter	146,962,000
Total	$ 293,007,000