Significant Non-Cash Investing Activities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Other Significant Noncash Transactions [Line Items]
Outstanding receivables from outside parties for the funding of capital expenditures	$ 449,995		$ 436,360
Purchases of property and equipment accrued in accounts payable	21,100	$ 8,800
Accounts receivable - grants from outside parties [Member]
Other Significant Noncash Transactions [Line Items]
Outstanding receivables from outside parties for the funding of capital expenditures	$ 17,263	$ 16,100	$ 19,376