Debt (Schedule of Interest Expense) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Mar. 31, 2015	Jun. 30, 2017	Jun. 30, 2016
Schedule of Interest Expense [Abstract]
Interest expense	$ 10,957	$ 9,991			$ 21,779	$ 19,505
Interest Costs Capitalized Adjustment	(94)	(196)	$ (160)	$ (316)
Gain (Loss) on Extinguishment of Debt	96	0			96	0
Amortization of debt issuance costs, debt discount and premium	869	871			1,774	1,739
Total interest expense	$ 11,828	$ 10,666			$ 23,489	$ 20,928