Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 5,189,072	$ 6,045,167
Less current portion	615,404	215,255
Total long-term debt and capital and financing lease obligations, less current portion	4,573,668	5,829,912
Mortgage Notes Payable [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	3,206,593	3,184,229
Unamortized debt discount	$ 7,800	$ 4,500
Weighted average interest rate	4.63%	4.50%
Capital and Financing Lease Obligations [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 1,591,264	$ 2,485,520
Weighted average interest rate	7.96%	8.08%
Convertible Debt [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 302,501	$ 295,397
Principal	316,300	316,300
Unamortized debt discount	$ 13,700	$ 20,900
Weighted average interest rate	2.75%	2.75%
Construction Financing [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 0	$ 3,644
Weighted average interest rate		8.00%
Notes Payable, Insurance Premiums [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 10,828	$ 0
Weighted average interest rate	2.94%
Other Notes Payable [Member]
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 77,886	$ 76,377
Weighted average interest rate	5.80%	5.33%