| Fair Value, Measurement Inputs, Disclosure [Text Block] |
The following assets and liabilities are measured at fair value on a recurring basis: | | | | | | | | | | | | | | | | | | December 31, 2013 | | Level 1 | | Level 2 | | Level 3 | | Total | | (Thousands of Dollars) | Other current assets: | | | | | | | | Product imbalances | $ | 1,980 |
| | $ | — |
| | $ | — |
| | $ | 1,980 |
| Commodity derivatives | — |
| | 4,948 |
| | — |
| | 4,948 |
| Other long-term assets, net: | | | | | | | | Commodity derivatives | — |
| | 6,977 |
| | — |
| | 6,977 |
| Accrued liabilities: | | | | | | | | Product imbalances | (2,190 | ) | | — |
| | — |
| | (2,190 | ) | Commodity derivatives | (1,433 | ) | | (800 | ) | | — |
| | (2,233 | ) | Contingent consideration | — |
| | — |
| | (1,318 | ) | | (1,318 | ) | Other long-term liabilities: | | | | | | | | Commodity derivatives | — |
| | (1,575 | ) | | — |
| | (1,575 | ) | Guarantee liability | — |
| | — |
| | (1,880 | ) | | (1,880 | ) | Total | $ | (1,643 | ) | | $ | 9,550 |
| | $ | (3,198 | ) | | $ | 4,709 |
|
| | | | | | | | | | | | | | | | | | December 31, 2012 | | Level 1 | | Level 2 | | Level 3 | | Total | | (Thousands of Dollars) | Other current assets: | | | | | | | | Product imbalances | $ | 1,232 |
| | $ | — |
| | $ | — |
| | $ | 1,232 |
| Commodity derivatives | 1,001 |
| | 8,357 |
| | — |
| | 9,358 |
| Other long-term assets, net: | | | | | | | | Commodity derivatives | — |
| | 9,206 |
| | — |
| | 9,206 |
| Accrued liabilities: | | | | | | | | Product imbalances | (1,686 | ) | | — |
| | — |
| | (1,686 | ) | Commodity derivatives | — |
| | (19,210 | ) | | — |
| | (19,210 | ) | Interest rate swaps | — |
| | (40,911 | ) | | — |
| | (40,911 | ) | Contingent consideration | — |
| | — |
| | (9,600 | ) | | (9,600 | ) | Total | $ | 547 |
| | $ | (42,558 | ) | | $ | (9,600 | ) | | $ | (51,611 | ) |
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| Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] |
The following table summarizes the activity in our Level 3 liabilities: | | | | | | Year Ended December 31, 2013 | | (Thousands of Dollars) | Beginning balance | $ | 9,600 |
| Amounts settled | (1,114 | ) | Adjustment to guarantee liability | 1,880 |
| Changes in fair value recorded in earnings: | | Operating expenses | (8,000 | ) | Interest expense, net | 832 |
| Ending balance | $ | 3,198 |
|
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| Fair Value and Carrying Value of Debt and Note Receivable from Related Party [Text Block] |
The estimated fair values and carrying amounts of our debt and note receivable from Asphalt JV were as follows: | | | | | | | | | | December 31, | | 2013 |
| 2012 | | (Thousands of Dollars) | Debt: | | | | Fair value | $ | 2,636,734 |
| | $ | 2,377,120 |
| Carrying amount | $ | 2,655,553 |
| | $ | 2,411,004 |
| | | | | Note Receivable from Related Party: | | | | Fair value | $ | 133,416 |
| | $ | 91,705 |
| Carrying amount | $ | 165,440 |
| | $ | 95,711 |
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