Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued capital expenditures	$ 92,506	$ 71,769
Accounts payable and accrued expenses	31,841	32,509
Interest rate swap agreements liability	0	436
Accrued interest payable	3,447	5,687
Due to affiliated companies	546	448
Total accounts payable and accrued expenses	$ 128,340	$ 110,849