Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ (56,690)	$ 81,917
Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities:
Depreciation and amortization	71,847	63,229
Stock compensation	5,001	3,767
Deferred income taxes	(29,764)	(7,451)
Equity earnings of investees, net of dividends	(4,533)	(1,274)
Amortization of debt issuance costs	1,594	1,667
Amortization of original issuance discount	3,343	3,070
(Gain) loss on disposition of assets	2,082	(572)
Unrealized (gain) loss on commodity swaps	7,144	(7,925)
Changes in operating assets and liabilities:
Accounts and other receivables, net	(45,014)	(9,264)
Income tax receivable	3,500	9,196
Inventories	(18,286)	5,436
Prepaid expenses and other current assets	(5,914)	1,690
Other assets, net	7,916	(293)
Accounts payable	45,741	(12,424)
Accrued liabilities	8,310	(6,409)
Other non-current liabilities	(8,286)	(8,469)
Net cash provided by (used in) operating activities	(12,009)	115,891
Cash flows from investing activities:
Capital expenditures	(37,230)	(31,051)
Capital expenditures for turnarounds and catalysts	(24,272)	(4,363)
Proceeds from disposition of assets	984	1,469
Acquisition of AltAir	7,936	0
Net cash used in investing activities	(68,454)	(33,945)
Cash flows from financing activities:
Dividends paid to stockholders	(21,155)	(17,384)
Dividends paid to non-controlling interest	(244)	(260)
Distributions paid to non-controlling interest in the Partnership	(921)	(16,224)
Inventory agreement transactions	82,724	30,135
Deferred debt issuance costs	0	1,800
Revolving credit facilities, net	0	(20,000)
Payments on long-term debt	(8,215)	(7,544)
Net cash provided by (used in) financing activities	52,189	(33,077)
Net increase (decrease) in cash and cash equivalents	(28,274)	48,869
Cash and cash equivalents, beginning of period	234,127	214,961
Cash and cash equivalents, end of period	205,853	263,830
Supplemental cash flow information:
Cash paid for interest, net of capitalized interest	33,312	35,660
Cash paid (refunds received) for income tax	$ (1,808)	$ 17,853