Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 43.7	$ 226.0	$ 135.7
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	134.0	111.5	89.8
Amortization of deferred financing costs	4.8	4.6	6.5
Accretion of asset retirement obligations	0.5	0.6	0.6
Amortization of unfavorable contract liability to revenue	0.0	(2.7)	(2.6)
Deferred income taxes	18.7	38.8	44.8
Income from equity method investments	(2.0)	0.0	0.0
Dividends from equity method investments	15.1	0.0	0.0
(Gain) loss on disposal of assets	(0.1)	(1.1)	1.6
Impairment of fixed assets	2.2	0.0	0.0
Equity-based compensation expense	16.8	13.9	15.0
Income tax benefit of equity-based compensation	(1.3)	(1.8)	(5.9)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(36.5)	55.4	5.8
Inventories and other current assets	114.0	217.0	(252.6)
Market value of derivatives	32.9	(59.9)	(8.8)
Accounts payable and other current liabilities	(75.8)	(104.4)	38.3
Obligation under Supply and Offtake Agreement,	(68.9)	(130.1)	45.8
Non-current assets and liabilities, net	(18.1)	(38.0)	(23.5)
Net cash provided by operating activities	180.0	329.8	90.5
Cash flows from investing activities:
Business combinations	(0.4)	(33.8)	(23.2)
Equity method investments	(240.9)	0.0	0.0
Purchases of property, plant and equipment	(214.1)	(269.8)	(210.3)
Purchase of intangible assets	(7.2)	0.0	0.0
Proceeds from sales of assets	2.2	1.3	1.3
Net cash used in investing activities	(460.4)	(302.3)	(232.2)
Cash flows from financing activities:
Proceeds from long-term revolvers	714.3	1,097.7	735.2
Payments on long-term revolvers	(572.2)	(995.2)	(663.9)
Proceeds from term debt and capital lease obligations	181.3	107.4	70.9
Payments on term debt and capital lease obligations	(78.6)	(30.2)	(94.1)
Proceeds from exercise of stock options	0.2	1.1	1.1
Taxes paid due to the net settlement of equity-based compensation	(4.4)	(5.2)	(2.5)
Income tax benefit of equity-based compensation	1.3	1.8	5.9
Repurchase of common stock	(42.2)	(74.7)	(37.9)
Distribution to non-controlling interest	(20.9)	(17.1)	(13.2)
Dividends paid	(37.1)	(59.2)	(57.3)
Deferred financing costs paid	(3.2)	(9.8)	(4.2)
Net cash provided by (used in) financing activities	138.5	16.6	(60.0)
Net (decrease) increase in cash and cash equivalents	(141.9)	44.1	(201.7)
Cash and cash equivalents at the beginning of the period	444.1	400.0	601.7
Cash and cash equivalents at the end of the period	302.2	444.1	400.0
Cash paid during the period for:
Interest, net of capitalized interest of $0.7 million, $1.5 million and $1.0 million in 2015, 2014 and 2013, respectively.	48.9	37.1	31.3
Income taxes	5.1	111.7	73.7
Non-cash investing activities:
Equity method investments	8.8	0.0	0.0
Increase (decrease) in accrued capital expenditures	4.5	(12.9)	12.0
Non-cash financing activities:
Stock issued in connection with the Alon Acquisition	230.8	0.0	0.0
Note payable issued in connection with the Alon Acquisition	$ 145.0	$ 0.0	$ 0.0