Debt (Interest Expense and Other Related Financing Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt [Abstract]
Interest expense and other financing costs	$ 3,720	$ 3,782	$ 7,817
Interest expense - beneficial conversion feature		45,915
Interest paid-in kind		14,695	11,434
Write-off of deferred financing costs and debt discount		3,820	2,752
Amortization of deferred financing costs, debt discount and debt premium	2,242	4,422	5,157
Interest expense	$ 5,962	$ 72,634	$ 27,160