Discontinued Operations and Assets Held for Sale (Major Categories of Assets and Liabilities Reflected as Held for Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current liabilities
Total current liabilities associated with assets held for sale	$ 12,607	$ 13,298
Discontinued Operations, Held-for-sale or Disposed of by Sale
Current assets
Cash	34,894	25,185
Accounts receivable	514	4,834
Inventories	406	406
Prepaid expenses and other	845	1,882
Property, Plant, and Equipment, net	42,348	82,116
Deferred income taxes and other assets	9,441	9,441
Total current assets associated with assets held for sale	88,448	123,864
Current liabilities
Accounts payable	3,076	3,702
Current maturities of long-term debt (finance lease)	709	705
Taxes payable	1,510	1,411
Long-term debt (finance lease)	7,067	7,240
Asset retirement obligation	245	240
Total current liabilities associated with assets held for sale	$ 12,607	$ 13,298