| Schedule of Changes in Current Assets and Liabilities [Text Block] |
Changes in current assets and current liabilities were as follows: | | | | | | | | | | | | | | Year Ended December 31, | | 2013 | | 2012 | | 2011 | | (Thousands of Dollars) | Decrease (increase) in current assets: | | | | | | Accounts receivable | $ | 107,209 |
| | $ | 160,435 |
| | $ | (230,980 | ) | Receivable from related parties | 58,692 |
| | (113,018 | ) | | — |
| Inventories | 31,975 |
| | 112,589 |
| | (160,139 | ) | Income tax receivable | 414 |
| | 2,921 |
| | (4,265 | ) | Other current assets | 25,725 |
| | (26,050 | ) | | (1,825 | ) | Increase (decrease) in current liabilities: | | | | | | Accounts payable | (96,330 | ) | | (43,451 | ) | | 140,898 |
| Payable to related party | 6,922 |
| | (5,339 | ) | | (3,603 | ) | Accrued interest payable | 9,370 |
| | (6,092 | ) | | 126 |
| Accrued liabilities | (32,452 | ) | | 11,259 |
| | (10,087 | ) | Taxes other than income tax | (87 | ) | | (2,444 | ) | | 2,574 |
| Income tax payable | 1,338 |
| | (563 | ) | | 1,848 |
| Changes in current assets and current liabilities | $ | 112,776 |
| | $ | 90,247 |
| | $ | (265,453 | ) |
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| Schedule of Supplemental Cash Flow Information [Text Block] |
Cash flows related to interest and income taxes were as follows: | | | | | | | | | | | | | | Year Ended December 31, | | 2013 | | 2012 | | 2011 | | (Thousands of Dollars) | Cash paid for interest, net of amount capitalized | $ | 113,805 |
| | $ | 110,679 |
| | $ | 109,027 |
| Cash paid for income taxes, net of tax refunds received | $ | 11,386 |
| | $ | 21,032 |
| | $ | 14,920 |
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