Financial Commitments (Summary of Interest Expense as Reported in the Consolidated Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Other interest	$ 532	$ 577	$ 1,422	$ 1,616
Cash portion of loss on extinguishment	0	786	0	786
Total cash interest expense	15,760	14,485	47,640	40,339
Non-cash interest expense			4,802	18,960
Non-cash portion of loss on extinguishment	0	8,311	0	8,311
Total non-cash interest expense	934	11,128	4,802	18,174
Total interest expense	16,694	25,613	52,442	58,513
Term Loan B
Debt Instrument [Line Items]
Cash interest expense	6,198	2,919	18,407	2,919
Non-cash interest expense	$ 547	253	$ 1,613	253
Effective interest rates	6.48%		6.48%
Convertible Notes
Debt Instrument [Line Items]
Cash interest expense		995	$ 921	3,870
Non-cash interest expense		2,073	$ 2,040	7,870
Effective interest rates	9.39%		9.39%
2017 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Cash interest expense	$ 8,594	8,594	$ 25,781	25,781
Non-cash interest expense	$ 245	229	$ 723	674
Effective interest rates	7.13%		7.13%
2020 Revolver
Debt Instrument [Line Items]
Cash interest expense	$ 436	26	$ 1,109	26
Non-cash interest expense	$ 142	64	$ 426	64
2017 Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Cash interest expense		588		5,341
Non-cash interest expense		$ 198		$ 1,002