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Variable interest entities (Details 6) - USD ($) $ in Thousands | Dec. 31, 2016 | Jun. 27, 2016 | Dec. 31, 2015 | Feb. 07, 2013
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Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Total project costs | $ 300,000 |  |  |
Portion of capital commitment | 150,000 |  |  |
Partner portion of capital commitment | 75,000 |  |  |
Excess capital commitments | 300,000 |  |  |
Term loan for project debt financing | 75,000 |  |  |
Fuel contract [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, reporting entity involvement, maximum loss exposure, amount | $ 43,300 |  |  |
Cash and cash equivalents [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | $ 851 |
Accounts receivable [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 7,693 |
Inventories [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 13,176 |
Other current assets [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 6,215 |
Total current assets [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 27,935 |
Net property, plant and equipment [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 425,123 |
Other [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 9,626 |
Total deferred charges and other assets [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 9,626 |
Total assets [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, assets |  |  | 462,684 |
Short-term borrowings [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 45,500 |
Long-term debt due within one year [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 5,250 |
Accounts payable [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 24,766 |
Taxes payable [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 1,391 |
Accrued compensation [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 938 |
Other accrued liabilities [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 4,953 |
Total current liabilities [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 82,798 |
Long-term debt [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | 63,750 |
Total liabilities [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Variable interest entity, consolidated, carrying amount, liabilities |  |  | $ 146,548 |
Calumet [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Previous percentage of ownership |  |  |  | 50.00%
Calumet [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Previous percentage of ownership |  |  |  | 50.00%
WBI Energy [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Previous percentage of ownership |  |  |  | 50.00%
Percentage of ownership acquired |  | 50.00% |  |
WBI Energy [Member] | Dakota Prairie Refining, LLC [Member] |  |  |  |
Variable Interest Entities [Line Items] |  |  |  |
Previous percentage of ownership |  |  |  | 50.00%
Percentage of ownership acquired |  | 50.00% |  |

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