Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 257,686	$ 256,947
Income taxes receivable	905	3,903
Other current assets	1,913	3,232
Total current assets	260,504	264,082
Right-of-use asset	661
Income taxes receivable, non-current	774	774
Investments in affiliates	94,406	24,574
Deferred tax assets	37,109	40,520
Other assets	343	350
Total assets	393,797	330,300
Current liabilities:
Accrued employment costs	1,664	2,573
Other current liabilities	1,605	1,495
Total current liabilities	3,269	4,068
Pension and other postretirement liabilities	15,052	15,167
Other liabilities	14,219	13,499
Total liabilities	32,540	32,734
Commitments and contingencies
Shareholders' Equity:
Preferred stock, 0.01 par value; 10,000,000 shares authorized, no shares issued and outstanding
Common Stock:
Paid-in capital	1,019,988	1,019,988
Accumulated deficit	(618,778)	(695,521)
Accumulated other comprehensive loss	(30,672)	(17,620)
Total shareholders' equity	361,257	297,566
Total liabilities and shareholders' equity	393,797	330,300
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