Financial Commitments (Summary Of Interest Expense As Reported In The Consolidated Statements of Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other interest	$ 2,079	$ 2,172	$ 2,747
Cash portion of loss on extinguishment	786	0	0
Total cash interest expense	56,059	54,287	51,447
Total non-cash interest expense	20,153	13,207	12,072
Non-cash portion of loss on extinguishment	8,312	0	0
Total interest expense	76,212	67,494	63,519
Term Loan B
Interest on debt	9,028
Total non-cash interest expense	$ 784
Effective interest rates	6.49%
Convertible Debt
Interest on debt	$ 4,373	5,750	5,750
Total non-cash interest expense	$ 8,944	10,811	9,846
Effective interest rates	9.39%
2017 Senior Notes | 2017 Senior Notes
Interest on debt	$ 34,375	34,375	34,375
Total non-cash interest expense	$ 906	844	787
Effective interest rates	7.13%
Credit Facility 2020
Interest on debt	$ 77
Total non-cash interest expense	206
2017 Credit Facility | Credit Facility
Interest on debt	5,341	11,990	8,575
Total non-cash interest expense	$ 1,001	$ 1,552	$ 1,439