Debt (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 6,206,284	$ 6,165,956
Less current portion	198,590	272,265
Long-term debt	6,007,694	5,893,691
Mortgage Notes Payable [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	3,216,847	3,105,410
Principal		316,300
Unamortized debt discount	$ 51,000	$ 59,600
Maturity date, start	Dec. 31, 2016
Maturity date, end	Dec. 31, 2047
Weighted average interest rate	4.79%	4.84%
Capital Lease Obligations [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 2,585,375	$ 2,649,226
Maturity date, start	Dec. 31, 2030
Weighted average interest rate	8.17%	8.57%
Convertible Debt [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 278,104	$ 272,345
Unamortized debt discount	$ 38,100	$ 43,900
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	$ 32,870	$ 50,118
Maturity date, start	Dec. 31, 2017
Maturity date, end	Dec. 31, 2019
Weighted average interest rate	5.85%	4.90%
Notes Payable, Insurance Premiums [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 9,652	$ 22,586
Maturity date, start	Dec. 31, 2015
Weighted average interest rate	2.82%	2.82%
Other Notes Payable [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Debt	$ 83,436	$ 66,271
Maturity date, start	Dec. 31, 2015
Maturity date, end	Dec. 31, 2020
Weighted average interest rate	5.52%	4.75%