Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 396,937		$ 447,766	$ 347,525		$ 336,997
Short-term investments		22,000		34,036
Accounts receivable, net		613,527		756,320
Inventory, net		186,124		165,587
Assets held for sale		8,037		12,250
Other current assets		153,723		177,604
Total current assets		1,380,348		1,593,563
Property, plant and equipment, net		5,152,236		5,467,870
Goodwill		90,543		183,914
Deferred income taxes		353,181		345,091
Other long-term assets		297,189		263,506
Total assets (1)	[1]	7,273,497		7,853,944
Current liabilities:
Current portion of debt		1,058		561
Trade accounts payable		364,658		392,843
Accrued liabilities		279,181		417,912
Income taxes payable		23,837		20,761
Current lease liabilities		13,570
Total current liabilities		682,304		832,077
Long-term debt		3,516,592		3,585,884
Other long-term liabilities		284,388		274,485
Deferred income taxes		29,109		6,311
Total liabilities (1)	[1]	4,512,393		4,698,757
Redeemable noncontrolling interest in subsidiary		420,217		404,861
Shareholders' equity		2,251,705		2,700,850
Noncontrolling interest		89,182		49,476
Total equity		2,340,887	$ 2,455,141	2,750,326	$ 2,963,828	$ 3,088,648	$ 2,938,773
Total liabilities and equity		7,273,497		7,853,944
Consolidating Adjustments
Current assets:
Intercompany receivables		(97,360)		(316,686)
Investment in consolidated affiliates		(12,224,472)		(12,232,982)
Deferred income taxes		(423,318)		(388,089)
Other long-term assets		(7,325)		(14,325)
Total assets (1)		(12,752,475)		(12,952,082)
Current liabilities:
Long-term debt		(7,325)		(14,325)
Deferred income taxes		(423,318)		(388,089)
Intercompany payable		(97,360)		(316,686)
Total liabilities (1)		(528,003)		(719,100)
Shareholders' equity		(12,224,472)		(12,232,982)
Total equity		(12,224,472)		(12,232,982)
Total liabilities and equity		(12,752,475)		(12,952,082)
Parent Company | Reportable Legal Entities
Current assets:
Cash and cash equivalents		349		474
Other current assets		172		50
Total current assets		521		524
Intercompany receivables		94,749		95,946
Investment in consolidated affiliates		2,167,547		2,658,827
Total assets (1)		2,262,817		2,755,297
Current liabilities:
Trade accounts payable		190		132
Accrued liabilities		8,374		28,815
Total current liabilities		8,564		28,947
Intercompany payable		2,548		25,500
Total liabilities (1)		11,112		54,447
Shareholders' equity		2,251,705		2,700,850
Total equity		2,251,705		2,700,850
Total liabilities and equity		2,262,817		2,755,297
Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash and cash equivalents		39		42
Other current assets				433
Total current assets		39		475
Intercompany receivables				218,129
Investment in consolidated affiliates		5,787,607		5,494,886
Deferred income taxes		423,318		388,089
Other long-term assets		132		142
Total assets (1)		6,211,096		6,101,721
Current liabilities:
Trade accounts payable		244		14
Accrued liabilities		18,558		62,830
Total current liabilities		18,802		62,844
Long-term debt		3,523,917		3,600,209
Other long-term liabilities		29,331		29,331
Intercompany payable		46,109
Total liabilities (1)		3,618,159		3,692,384
Shareholders' equity		2,592,937		2,409,337
Total equity		2,592,937		2,409,337
Total liabilities and equity		6,211,096		6,101,721
Other Subsidiaries (Non-Guarantors) | Reportable Legal Entities
Current assets:
Cash and cash equivalents		396,549		447,250
Short-term investments		22,000		34,036
Accounts receivable, net		613,527		756,320
Inventory, net		186,124		165,587
Assets held for sale		8,037		12,250
Other current assets		153,551		177,121
Total current assets		1,379,788		1,592,564
Property, plant and equipment, net		5,152,236		5,467,870
Goodwill		90,543		183,914
Intercompany receivables		2,611		2,611
Investment in consolidated affiliates		4,269,318		4,079,269
Deferred income taxes		353,181		345,091
Other long-term assets		304,382		277,689
Total assets (1)		11,552,059		11,949,008
Current liabilities:
Current portion of debt		1,058		561
Trade accounts payable		364,224		392,697
Accrued liabilities		252,249		326,267
Income taxes payable		23,837		20,761
Current lease liabilities		13,570
Total current liabilities		654,938		740,286
Other long-term liabilities		255,057		245,154
Deferred income taxes		452,427		394,400
Intercompany payable		48,703		291,186
Total liabilities (1)		1,411,125		1,671,026
Redeemable noncontrolling interest in subsidiary		420,217		404,861
Shareholders' equity		9,631,535		9,823,645
Noncontrolling interest		89,182		49,476
Total equity		9,720,717		9,873,121
Total liabilities and equity		$ 11,552,059		$ 11,949,008
Purchasers
Condensed Consolidating Financial Information
Ownership percentage		100.00%

[1] The condensed consolidated balance sheet as of September 30, 2019 and December 31, 2018 include assets and liabilities of variable interest entities. See Note 3—Joint Ventures for additional information.