Financial Commitments (Summary Of Interest Expense As Reported In The Condensed Consolidated Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other interest	$ 736	$ 802	$ 2,119	$ 2,495
Cash portion of loss on extinguishment				1,913
Non-cash portion of loss on extinguishment				5,139
Total cash interest expense	13,363	12,868	38,512	39,001
Total non-cash interest expense	3,048	2,775	8,962	14,725
Total interest expense	16,411	15,643	47,474	53,726
Convertible Notes [Member]
Interest on debt	1,437	1,438	4,312	4,313
Total non-cash interest expense	$ 2,490	2,268	$ 7,298	6,646
Effective interest rates	9.39%		9.39%
2017 Senior Notes [Member] | Senior Notes [Member]
Interest on debt	$ 8,594	8,593	$ 25,781	15,373
Total non-cash interest expense	$ 198	185	$ 584	326
Effective interest rates	7.13%		7.13%
2017 Credit Facility [Member] | Credit Facility [Member]
Interest on debt	$ 2,596	2,035	$ 6,300	3,526
Total non-cash interest expense	$ 360	$ 322	$ 1,080	603
2010 Senior Notes [Member] | Senior Notes [Member]
Interest on debt				6,926
Total non-cash interest expense				308
2014 Credit Facility [Member] | Credit Facility [Member]
Interest on debt				4,455
Total non-cash interest expense				$ 1,703