SENIOR NOTES PAYABLE AND OTHER DEBT (Details 4) (USD $)	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2012	$ 23,240,000
2013	614,045,000
2014	338,540,000
2015	1,817,661,000
2016	446,154,000
Thereafter	4,024,465,000
Total maturities	7,264,105,000	6,180,443,000
Unrestricted cash and cash equivalents	58,530,000	45,807,000	57,482,000	41,899,000	21,812,000
Unsecured revolving credit facilities
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total maturities	704,770,000	455,578,000
Unrestricted cash and cash equivalents	58,500,000
Amount outstanding, net of cash and cash equivalents	646,200,000
Extension of maturity date	1 year
Mortgage loans
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Total maturities	23,400,000	14,600,000
6.90% Senior Notes due 2037 | NHP
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Thereafter	52,400,000
6.59% senior notes due 2038 | NHP
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
Thereafter	23,000,000
Principal Amount Due at Maturity
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2012	9,031,000
2013	562,366,000
2014	291,030,000
2015	1,074,793,000
2016	415,334,000
Thereafter	3,846,022,000
Total maturities	6,198,576,000
Unsecured Revolving Credit Facility
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2012	0
2013	0
2014	0
2015	704,770,000
2016	0
Thereafter	0
Total maturities	704,770,000
Scheduled Periodic Amortization
Scheduled maturities of borrowing arrangements and other provisions excluding capital lease obligations
2012	14,209,000
2013	51,679,000
2014	47,510,000
2015	38,098,000
2016	30,820,000
Thereafter	178,443,000
Total maturities	$ 360,759,000