Major classes of assets and liabilities Refining (Details 2) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Current assets:
Total current assets held for sale		$ 572	$ 479	$ 328
Current liabilities:
Total current liabilities held for sale		11,713	11,993	4,481
Refining | Discontinued operations, held-for-sale or disposed of by sale
Current assets:
Income taxes receivable	[1]	1,689	1,778	5,552
Total current assets held for sale		1,689	1,778	5,552
Total assets held for sale		1,689	1,778	5,552
Noncurrent liabilities:
Deferred income taxes (b)	[2]	37	37	55
Total noncurrent liabilities held for sale		37	37	55
Total liabilities held for sale		$ 37	$ 37	$ 55

[1] On the Company's Consolidated Balance Sheets, these amounts were reclassified to taxes payable and are reflected in current liabilities held for sale.

[2] On the Company's Consolidated Balance Sheets, these amounts were reclassified to deferred charges and other assets - deferred income taxes and are reflected in noncurrent assets held for sale.