Non-operating (loss) income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Non-operating (loss) income, net [Abstract]
Unrealized Gain (Loss) on Derivatives	$ 2,708	$ 5,246	$ (4,311)	$ 10,515
Interest and Dividend Income, Securities	373	195	632	511
Other Nonoperating Income (Expense)	120	(447)	1,325	484
Nonoperating (loss) Income	$ 3,201	$ 4,994	$ (2,354)	$ 11,510