SENIOR NOTES PAYABLE AND OTHER DEBT (Details 3) (USD $)	3 Months Ended		9 Months Ended				1 Months Ended			1 Months Ended	3 Months Ended			1 Months Ended			1 Months Ended			1 Months Ended			1 Months Ended			1 Months Ended	3 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 Unsecured term loan	Feb. 29, 2012 4.25% senior notes due 2022	Sep. 30, 2012 4.25% senior notes due 2022	Dec. 31, 2011 4.25% senior notes due 2022	Mar. 31, 2012 6 1/2% Senior Notes due 2016	Mar. 31, 2012 6 1/2% Senior Notes due 2016	Sep. 30, 2012 6 1/2% Senior Notes due 2016	Dec. 31, 2011 6 1/2% Senior Notes due 2016	Apr. 30, 2012 4.00% senior notes due 2019	Sep. 30, 2012 4.00% senior notes due 2019	Dec. 31, 2011 4.00% senior notes due 2019	Jul. 31, 2012 8 1/4% Senior Notes due 2012	Sep. 30, 2012 8 1/4% Senior Notes due 2012	Dec. 31, 2011 8 1/4% Senior Notes due 2012	Aug. 31, 2012 3.25% senior notes due 2022	Sep. 30, 2012 3.25% senior notes due 2022	Dec. 31, 2011 3.25% senior notes due 2022	May 31, 2012 9% Senior Notes due 2012	Sep. 30, 2012 9% Senior Notes due 2012	Dec. 31, 2011 9% Senior Notes due 2012	May 31, 2012 6 3/4% Senior Notes due 2017	Jun. 30, 2012 6 3/4% Senior Notes due 2017	Sep. 30, 2012 6 3/4% Senior Notes due 2017	Dec. 31, 2011 6 3/4% Senior Notes due 2017	Sep. 30, 2012 Mortgage loans	Dec. 31, 2011 Mortgage loans
Debt instruments
Principal amount of debt issued							$ 600,000,000							$ 600,000,000						$ 275,000,000
Interest rate (as a percent)							4.25%	4.25%	4.25%	6.50%	6.50%	6.50%	6.50%	4.00%	4.00%	4.00%	8.25%	8.25%	8.25%	3.25%	3.25%	3.25%	9.00%	9.00%	9.00%	6.75%		6.75%	6.75%
Public Offering Price as a Percent of Par							99.214%							99.489%						99.027%
Proceeds from issuance of debt							595,300,000							596,900,000						272,300,000
Principal amount of debt redeemed										200,000,000							73,000,000						82,400,000			225,000,000
Senior Note Redemption Price as a Percent of Par										103.25%	103.25%															103.375%
Repayments of senior debt										206,500,000																232,600,000
Net loss on extinguishment of debt	(1,194,000)	8,685,000	38,339,000	25,211,000							29,700,000																10,000,000
Principal amount outstanding	$ 7,264,105,000		$ 7,264,105,000		$ 6,180,443,000	$ 500,000,000		$ 600,000,000	$ 0			$ 0	$ 200,000,000		$ 600,000,000	$ 0		$ 0	$ 72,950,000		$ 275,000,000	$ 0		$ 0	$ 82,433,000			$ 0	$ 225,000,000	$ 23,400,000	$ 14,600,000