Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 42,310	$ 48,626
Accounts receivable (net of allowance of $1,116 and $671 at June 30, 2020 and December 31, 2019, respectively)	13,019	18,441
Notes receivable	22,775
Inventories	3,060	2,573
Prepaids and other current assets	8,550	5,164
Total current assets	89,714	74,804
Property, plant and equipment, at cost	314,418	343,893
Less accumulated depreciation	(299,237)	(325,440)
Property, plant and equipment, net	15,181	18,453
Operating lease right-of-use assets	21,871	21,371
Intangible assets, net	191	319
Deferred income taxes, net	22	50
Long-term note receivable		22,400
Other assets	3,627	3,648
Total assets	130,606	141,045
Current liabilities:
Accounts payable	4,903	6,103
Accrued compensation and benefits	5,733	7,407
Other accrued expense	6,359	5,930
Contract liabilities	14,012	12,098
Total current liabilities	31,007	31,538
Long-term pension liabilities	20,275	23,039
Long-term operating lease liabilities	23,051	23,120
Other post-employment benefits	1,330	1,347
Other liabilities	4,372	4,264
Total liabilities	80,035	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 June 30, 2020 and December 31, 2019	(13,443)	(13,443)
Additional paid-in capital	494,389	494,389
Accumulated other comprehensive loss	(31,856)	(32,294)
Accumulated deficit	(398,752)	(391,148)
Total shareholders’ equity	50,571	57,737
Total liabilities and shareholders’ equity	130,606	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