Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 43,174	$ 48,626
Accounts receivable (net of allowance of $829 and $671 at September 30, 2020 and December 31, 2019, respectively)	15,174	18,441
Notes receivable	22,775
Inventories	2,062	2,573
Prepaids and other current assets	8,344	5,164
Total current assets	91,529	74,804
Property, plant and equipment, at cost	313,667	343,893
Less accumulated depreciation	(300,188)	(325,440)
Property, plant and equipment, net	13,479	18,453
Operating lease right-of-use assets	21,496	21,371
Intangible assets, net	128	319
Deferred income taxes, net	27	50
Long-term note receivable		22,400
Other assets	2,608	3,648
Total assets	129,267	141,045
Current liabilities:
Accounts payable	5,792	6,103
Accrued compensation and benefits	6,835	7,407
Other accrued expense	5,778	5,930
Contract liabilities	14,860	12,098
Total current liabilities	33,265	31,538
Long-term pension liabilities	18,893	23,039
Long-term operating lease liabilities	22,555	23,120
Other post-employment benefits	1,322	1,347
Other liabilities	3,396	4,264
Total liabilities	79,431	83,308
Shareholders' equity:
Preferred stock, $.01 par value; Authorized 2,000,000 shares; none issued
Treasury stock, Series A, at cost; 1,913,860 shares held at September 30, 2020 and December 31, 2019	(13,443)	(13,443)
Additional paid-in capital	494,389	494,389
Accumulated other comprehensive loss	(31,637)	(32,294)
Accumulated deficit	(399,706)	(391,148)
Total shareholders’ equity	49,836	57,737
Total liabilities and shareholders’ equity	129,267	141,045
Series A
Shareholders' equity:
Common stock, $.01 par value; Authorized 125,000,000 shares	209	209
Series B
Shareholders' equity:
Common stock, $.01 par value; Authorized 125,000,000 shares	$ 24	$ 24