Debt (Details) - USD ($) $ in Thousands	Sep. 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	$ 5,515,367	$ 6,045,167
Less current portion	646,504	215,255
Total long-term debt and capital and financing lease obligations, less current portion	4,868,863	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	3,550,927	3,184,229
Unamortized debt discount	$ 15,600	$ 4,500
Weighted average interest rate	4.58%	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	$ 1,577,589	$ 2,485,520
Weighted average interest rate	7.95%	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	$ 306,145	$ 295,397
Principal	316,300	316,300
Unamortized debt discount	$ 10,100	$ 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	$ 4,347	$ 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	$ 76,359	$ 76,377
Weighted average interest rate	5.80%	5.33%