Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 31,631	$ 259,067
Income tax refund receivable	1,228	576
Other current assets	1,232	1,322
Total current assets	34,091	260,965
Right-of-use asset	342	988
Income tax refund receivable, non-current	0	387
Investments in affiliates	192,664	90,184
Deferred tax assets	27,339	37,945
Other assets	33	341
Total assets	254,469	390,810
Current liabilities:
Accrued employment costs	2,839	2,611
Other current liabilities	2,002	2,883
Total current liabilities	4,841	5,494
Pension and other post-retirement liabilities	20,181	17,447
Other liabilities	19,914	17,842
Total liabilities	44,936	40,783
Commitments and contingencies
Shareholders' Equity:
Preferred stock, $0.01 par value	0	0
Common Stock:
Paid-in capital	1,019,988	1,019,988
Accumulated deficit	(729,202)	(605,766)
Accumulated other comprehensive loss	(71,972)	(54,914)
Total shareholders' equity	209,533	350,027
Total liabilities and shareholders' equity	254,469	390,810
Voting Common Stock [Member]
Common Stock:
Common stock, $0.01 par value	216	216
Treasury stock (at cost), 154,494 shares of voting common stock	(9,592)	(9,592)
Nonvoting Common Stock [Member]
Common Stock:
Common stock, $0.01 par value	95	95
Series A Preferred Stock [Member]
Shareholders' Equity:
Preferred stock, $0.01 par value	0	0
Series B Preferred Stock [Member]
Shareholders' Equity:
Preferred stock, $0.01 par value	$ 0	$ 0