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Other Financial Information (Tables) | 9 Months Ended
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Sep. 30, 2016
Other Financial Information [Abstract] |
Schedule of Renewable Identification Numbers (RINS) and Other Revenue | Other operating revenues in the Consolidated Statements of Income include the following items:
| Three Months Ended September 30, |  | Nine Months Ended September 30,
(Thousands of dollars) | 2016 |  | 2015 |  | 2016 |  | 2015
Renewable Identification Numbers (RINs) sales | $ | 48,047 |  |  | $ | 20,037 |  |  | $ | 130,690 |  |  | $ | 93,883 |
Other | 772 |  |  | 717 |  |  | 2,940 |  |  | 2,331 |
Other operating revenues | $ | 48,819 |  |  | $ | 20,754 |  |  | $ | 133,630 |  |  | $ | 96,214 |
Summary of Changes in Operating Working Capital |
| Nine Months Ended September 30,
(Thousands of dollars) | 2016 |  | 2015
Accounts receivable | $ | (3,403 | ) |  | $ | (5,742 | )
Inventories | 3,364 |  |  | (8,082 | )
Prepaid expenses and other current assets | 11,891 |  |  | (63 | )
Accounts payable and accrued liabilities | (6,289 | ) |  | (16,642 | )
Income taxes payable | (181 | ) |  | (11,695 | )
Current deferred income tax liabilities | — |  |  | 9,030 |
Net decrease (increase) in noncash operating working capital | $ | 5,382 |  |  | $ | (33,194 | )

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- Definition Schedule of Renewable Identification Numbers (RINS) and Other Revenue [Table Text Block] + References No definition available. + Details
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- Definition Tabular disclosure of the net increase (decrease) in operating capital in the operating section of the statement of cash flows, represents the entire footnote disclosure that provides details regarding the net change during the reporting period of all assets and liabilities used in operating activities. + References No definition available. + Details
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