Financial Commitments (Summary of Interest Expense as Reported in the Consolidated Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Other interest	$ 481	$ 504
Total cash interest expense	15,793	12,950
Non-cash interest expense	2,017	3,486
Total non-cash interest expense	2,017	3,486
Total interest expense	17,810	16,436
Term Loan B
Debt Instrument [Line Items]
Cash interest expense	6,094
Non-cash interest expense	$ 539
Effective interest rates	6.49%
Convertible Notes
Debt Instrument [Line Items]
Cash interest expense	$ 503	1,437
Non-cash interest expense	$ 1,099	2,864
Effective interest rates	9.39%
2017 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Cash interest expense	$ 8,594	8,594
Non-cash interest expense	$ 237	220
Effective interest rates	7.13%
2020 Revolver
Debt Instrument [Line Items]
Cash interest expense	$ 121
Non-cash interest expense	$ 142
2017 Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Cash interest expense		2,415
Non-cash interest expense		$ 402