Debt (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 6,201,202	$ 6,122,413
Less current portion	332,551	235,604
Long-term debt	5,868,651	5,886,809
Mortgage Notes Payable [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	3,307,932	3,246,513
Unamortized debt discount	$ 300	$ 3,300
Maturity date, start	Dec. 31, 2017
Maturity date, end	Dec. 31, 2047
Weighted average interest rate	4.58%	4.51%
Capital and Financing Lease Obligations [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 2,492,546	$ 2,489,588
Maturity date, start	Dec. 31, 2031
Weighted average interest rate	8.07%	8.11%
Convertible Debt [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 288,534	$ 281,902
Principal	316,300	316,300
Unamortized debt discount	$ 27,700	$ 34,300
Maturity date, start	Jun. 30, 2018
Weighted average interest rate	2.75%	2.75%
Construction Financing [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 21,809	$ 24,105
Maturity date, start	Dec. 31, 2019
Maturity date, end	Dec. 31, 2032
Weighted average interest rate	7.76%	4.84%
Notes Payable, Insurance Premiums [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 11,089	$ 0
Maturity date, start	Dec. 31, 2016
Weighted average interest rate	2.94%
Other Notes Payable [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 79,292	$ 80,305
Maturity date, start	Dec. 31, 2016
Maturity date, end	Dec. 31, 2020
Weighted average interest rate	5.26%	5.16%