Debt (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Debt Disclosure [Abstract]
Interest payments on debt facilities	$ 18,000	$ 18,500	$ 54,000	$ 53,200
Capitalized interest	$ 37	$ 1,500	$ 200	$ 3,400