Major classes of assets and liabilities refining (Details 2) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Total current assets held for sale	$ 430	$ 479
Refining [Member] | Discontinued operations, held-for-sale or disposed by sale [Member]
Current assets:
Income taxes receivable	0	1,778
Total current assets held for sale	0	1,778
Total assets held for sale	0	1,778
Deferred credits and other liabilities:
Deferred income taxes	0	37
Total noncurrent liabilities held for sale	0	37
Total liabilities held for sale	$ 0	$ 37