Acquisitions - Updates to Purchase Price Allocation (Details) - Alon $ in Millions	3 Months Ended
	Jun. 30, 2018 USD ($)
Business Acquisition [Line Items]
Receivables	$ 10.7	[1]
Inventories	(0.5)
Prepaids And Other Current Assets	9.7	[2]
Property, Plant, and Equipment	(0.2)
Acquired intangible assets	7.7	[3]
Accounts Payable	(6.0)	[4]
Obligation Under Supply Agreements	(10.9)	[5]
Current portion of environmental liabilities	0.4
Other Current Liabilities	(22.3)	[6]
Environmental liabilities and asset retirement obligations, net of current portion	(65.3)	[7]
Deferred Income Tax	8.4	[8]
Other Noncurrent Liabilities	2.8	[9]
Resulting adjustment to goodwill	$ 66.3

[1] Change primarily relates to the recognition of a receivable associated with a third-party indemnification agreement for asset retirement obligations for one of the acquired refineries that was previously under review, and finalization of an accrued receivable estimate.

[2] Change primarily relates to a reclassification of Renewable Identification Numbers ("RINs") assets from other current liabilities to other current assets.

[3] Change is primarily due to the addition of an intangible asset for certain below-market leases that had previously been identified but for which the evaluation and determination of fair value was not complete at December 31, 2017.

[4] Change is primarily due to the elimination of amounts in accounts payable in the retail segment that were determined not to have value combined with reclassifications of amounts to accounts receivable.

[5] Change relates to true-up of certain accounts related to one of the acquired supply and offtake agreements for contractual terms that were previously under review.

[6] Change is primarily due to an increase related to the reclassification of RINs assets from other current liabilities to other current assets and an increase related to the accrual of certain executive bonuses that were required under existing Alon employment agreements and related to service provided prior to the Delek/Alon Merger, net of adjustments to current income taxes payable to true up income taxes related to the acquired net assets.

[7] Change is to record the long-term portion of additional asset retirement obligations and environmental liabilities identified and/or to update preliminary estimates based on additional information.

[8] Change is related to adjustments to net deferred tax liabilities based on the updated purchase price allocation and revisions of preliminary tax estimates.

[9] Change is related to the reversal of an accrual established in the purchase price allocation related to a pre-acquisition legal contingency that was resolved during the first quarter 2018 in our favor.