Interest Expense Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest expense	$ 23,465	$ 16,378	$ 69,024	$ 45,011
Amortization of deferred financing costs	1,043	739	3,501	1,527
Unrealized Gain (Loss) on Derivatives	(287)	467	1,264	467
Derivative, Gain (Loss) on Derivative, Net	(135)	27	(135)	27
Capitalized interest	(5,681)	(1,368)	(14,863)	(2,285)
Interest Expense	$ 18,979	$ 15,309	$ 56,263	$ 43,813