Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ (17,150,000)	$ 13,262,000	$ 42,812,000
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	158,421,000	98,804,000	100,882,000
Loss on disposal or impairment, net	13,333,000	16,048,000	11,472,000
Equity earnings from investments	(67,331,000)	(73,757,000)	(81,386,000)
Loss (gain) on issuance of common units by equity method investee	0	41,000	(6,385,000)
Loss (gain) on sale or impairment of non-operated equity method investment	0	30,644,000	(14,517,000)
Distributions from equity investments	66,748,000	76,442,000	95,429,000
Amortization and write down of debt issuance costs	6,221,000	7,561,000	5,102,000
Loss on early extinguishment of debt	19,930,000	0	0
Deferred tax expense (benefit)	(9,829,000)	8,447,000	29,197,000
Non-cash compensation expense	10,253,000	10,216,000	10,617,000
Provision for uncollectible accounts receivable, net of recoveries	165,000	(527,000)	208,000
Gain on pension curtailment	(3,008,000)	0	0
Inventory valuation adjustment	455,000	0	2,590,000
Foreign currency transaction loss (gain)	(4,709,000)	4,759,000	(1,067,000)
Changes in operating assets and liabilities (Note 21)	(33,023,000)	(21,966,000)	(13,192,000)
Net cash provided by operating activities	140,476,000	169,974,000	181,762,000
Cash flows from investing activities:
Capital expenditures	(462,713,000)	(312,456,000)	(479,530,000)
Proceeds from sale of equity method investment and other long-lived assets	314,821,000	151,000	3,688,000
Investments in non-consolidated subsidiaries	(26,444,000)	(4,188,000)	(46,730,000)
Payments to acquire business, net of cash acquired	294,239,000	0	0
Proceeds from sale of common units of equity method investee	0	60,483,000	56,318,000
Distributions from equity method investments in excess of equity in earnings	28,774,000	27,726,000	24,113,000
Net cash provided by (used in) investing activities	(439,801,000)	(228,284,000)	(442,141,000)
Cash flows from financing activities:
Debt issuance costs	(11,116,000)	(7,728,000)	(6,289,000)
Borrowings on credit facilities and issuance of senior unsecured notes	1,525,377,000	382,500,000	867,208,000
Principal payments on debt and other obligations	(1,052,428,000)	(396,890,000)	(560,049,000)
Debt extinguishment costs	(16,293,000)	0	0
Distributions to noncontrolling interests	0	(32,133,000)	(40,410,000)
Repurchase of common stock for payment of statutory taxes due on equity-based compensation	(1,473,000)	(965,000)	(4,261,000)
Dividends paid	(129,925,000)	(92,910,000)	(69,514,000)
Proceeds from issuance of common stock under employee stock purchase plan	1,114,000	1,010,000	1,223,000
Proceeds from issuance of common shares, net of offering costs	0	223,025,000	0
Rose Rock equity issuance	0	0	89,119,000
Net cash provided by (used in) financing activities	315,256,000	75,909,000	277,027,000
Effect of exchange rate changes on cash and cash equivalents	3,552,000	(1,479,000)	850,000
Change in cash and cash equivalents	19,483,000	16,120,000	17,498,000
Cash and cash equivalents at beginning of period	74,216,000	58,096,000	40,598,000
Cash and cash equivalents at end of period	$ 93,699,000	$ 74,216,000	$ 58,096,000