Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 4,632,959	$ 5,142,291
Less current portion	503,687	602,501
Total long-term debt and capital and financing lease obligations, less current portion	4,129,272	4,539,790
Mortgage notes payable
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	3,633,919	3,497,762
Unamortized debt discount	$ 20,200	$ 16,600
Weighted average interest rate	4.76%	4.59%
Capital and finance lease obligations
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 932,918	$ 1,271,554
Weighted average interest rate	8.13%	6.75%
Convertible notes payable
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 0	$ 309,853
Principal		316,300
Unamortized debt discount		$ 6,400
Weighted average interest rate		2.75%
Other notes payable
Long-Term Debt, Capital and Financing Leases and Financing Obligations [Line Items]
Total long-term debt and capital and financing lease obligations	$ 66,122	$ 63,122
Weighted average interest rate	5.69%	5.98%