Senior Notes Payable and Other Debt (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Principal Amount Due at Maturity [Member]	Nov. 02, 2011 Unsecured Revolving Credit Facilities [Member]	Sep. 30, 2011 Unsecured Revolving Credit Facilities [Member]		Sep. 30, 2011 Scheduled Periodic Amortization [Member]	Sep. 30, 2011 3 7/8 % Convertible Senior Notes due 2011 [Member]	Dec. 31, 2010 3 7/8 % Convertible Senior Notes due 2011 [Member]	Sep. 30, 2011 9% Senior Notes due 2012 [Member]	Dec. 31, 2010 9% Senior Notes due 2012 [Member]	Sep. 30, 2011 3.125% Senior Notes due 2015 [Member]	Dec. 31, 2010 3.125% Senior Notes due 2015 [Member]	Sep. 30, 2011 8 1/4% Senior Notes due 2012 [Member]	Sep. 30, 2011 Unsecured term loan due 2012 [Member]	Sep. 30, 2011 Unsecured term loan due 2013 [Member]	Dec. 31, 2010 Unsecured term loan due 2013 [Member]	Sep. 30, 2011 6.25% Senior Notes due 2013 [Member]	Sep. 30, 2011 6% Senior Notes due 2015 [Member]	Sep. 30, 2011 6.90% Senior Notes due 2037 [Member]	Sep. 30, 2011 6.59% Senior Notes due 2038 [Member]	Sep. 30, 2011 6 1/2% Senior Notes due 2016 [Member]	Dec. 31, 2010 6 1/2% Senior Notes due 2016 [Member]	Sep. 30, 2011 6 3/4% Senior Notes due 2017 [Member]	Dec. 31, 2010 6 3/4% Senior Notes due 2017 [Member]	Sep. 30, 2011 4.750% Senior Notes due 2021 [Member]
Long-term debt and certain interest rate and maturity information
Line of credit	$ 474,000,000	$ 40,000
Senior Notes								230,000	230,000	82,433	82,433	400,000	400,000	72,950				269,850	234,420	52,400	22,973	200,000	400,000	225,000	225,000	700,000
Unsecured term loan due				727,000											250,000	200,000	200,000
Mortgage loans and other	2,651,830	1,349,521
Total	6,065,856	2,926,954	5,217,370		474,000	[1]	374,486
Capital lease obligations	143,119
Unamortized fair value adjustment	145,647	11,790
Unamortized commission fees and discounts	(41,481)	(38,700)
Senior notes payable and other debt	$ 6,313,141	$ 2,900,044

[1] At September 30, 2011, we had $57.5 million of unrestricted cash and cash equivalents, for $416.5 million of net borrowings outstanding under our unsecured revolving credit facilities. On October 18, 2011, we repaid all borrowings outstanding and terminated the commitments under our unsecured revolving credit facilities and entered into a new $2.0 billion unsecured revolving credit facility due 2015. See "Unsecured Revolving Credit Facilities and Term Loans" below.