Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 190,556	$ 264,093	$ 177,043	$ 254,530
Short-term investments	29,770	31,109
Accounts receivable, net	621,640	508,355
Inventory, net	119,050	103,595
Assets held for sale	37,275	76,668
Other current assets	176,630	172,019
Total current assets	1,174,921	1,155,839
Property, plant and equipment, net	6,051,606	6,267,583
Goodwill	173,321	166,917
Deferred tax assets	444,796	366,586
Other long-term assets	243,941	230,090
Total assets	8,088,585	8,187,015
Current liabilities:
Less: current portion	196	297
Trade accounts payable	317,314	264,578
Accrued liabilities	485,347	543,248
Income taxes payable	27,817	13,811
Total current liabilities	830,674	821,934
Long-term Debt, Excluding Current Maturities, Total	3,958,615	3,578,335
Other long-term liabilities	351,787	522,456
Deferred Tax Liabilities, Net, Noncurrent3	20,288	9,495
Total liabilities	5,161,364	4,932,220
Shareholders' equity	2,901,405	3,247,025
Noncontrolling interest	25,816	7,770
Total equity	2,927,221	3,254,795	3,598,694	4,293,868
Total liabilities and equity	8,088,585	8,187,015
Reportable Legal Entities | Parent Company
Current assets:
Cash and cash equivalents	386	1,148	1,055	873
Other current assets	50	50
Total current assets	436	1,198
Intercompany receivables	134,757	142,447
Investment in consolidated affiliates	2,789,805	3,170,254
Total assets	2,924,998	3,313,899
Current liabilities:
Trade accounts payable	426	205
Accrued liabilities	21,167	20,669
Total current liabilities	21,593	20,874
Intercompany payable	2,000	46,000
Total liabilities	23,593	66,874
Shareholders' equity	2,901,405	3,247,025
Total equity	2,901,405	3,247,025
Total liabilities and equity	2,924,998	3,313,899
Reportable Legal Entities | Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	47	10,177	8	10
Other current assets	27,869	22,209
Total current assets	27,916	32,386
Intercompany receivables	417,432
Investment in consolidated affiliates	5,411,796	4,830,572
Deferred tax assets	514,579	443,049
Other long-term assets	147	344
Total assets	6,371,870	5,306,351
Current liabilities:
Trade accounts payable	171	8
Accrued liabilities	21,972	65,246
Total current liabilities	22,143	65,254
Long-term Debt, Excluding Current Maturities, Total	4,030,758	3,796,550
Other long-term liabilities	22,870	22,659
Intercompany payable		1,439,390
Total liabilities	4,075,771	5,323,853
Shareholders' equity	2,296,099	(17,502)
Total equity	2,296,099	(17,502)
Total liabilities and equity	6,371,870	5,306,351
Reportable Legal Entities | Other Subsidiaries (Non-Guarantors)
Current assets:
Cash and cash equivalents	190,123	252,768	$ 175,980	$ 253,647
Short-term investments	29,770	31,109
Accounts receivable, net	621,640	508,355
Inventory, net	119,050	103,595
Assets held for sale	37,275	76,668
Other current assets	148,711	149,760
Total current assets	1,146,569	1,122,255
Property, plant and equipment, net	6,051,606	6,267,583
Goodwill	173,321	166,917
Intercompany receivables		1,342,942
Investment in consolidated affiliates	3,875,639	1,083,948
Deferred tax assets	444,796	366,586
Other long-term assets	315,937	447,962
Total assets	12,007,868	10,798,193
Current liabilities:
Less: current portion	196	297
Trade accounts payable	316,717	264,365
Accrued liabilities	442,208	457,333
Income taxes payable	27,817	13,811
Total current liabilities	786,938	735,806
Other long-term liabilities	328,917	499,797
Deferred Tax Liabilities, Net, Noncurrent3	534,867	452,544
Intercompany payable	550,189
Total liabilities	2,200,911	1,688,147
Shareholders' equity	9,781,141	9,102,276
Noncontrolling interest	25,816	7,770
Total equity	9,806,957	9,110,046
Total liabilities and equity	12,007,868	10,798,193
Consolidating Adjustments
Current assets:
Intercompany receivables	(552,189)	(1,485,389)
Investment in consolidated affiliates	(12,077,240)	(9,084,774)
Deferred tax assets	(514,579)	(443,049)
Other long-term assets	(72,143)	(218,216)
Total assets	(13,216,151)	(11,231,428)
Current liabilities:
Long-term Debt, Excluding Current Maturities, Total	(72,143)	(218,215)
Deferred Tax Liabilities, Net, Noncurrent3	(514,579)	(443,049)
Intercompany payable	(552,189)	(1,485,390)
Total liabilities	(1,138,911)	(2,146,654)
Shareholders' equity	(12,077,240)	(9,084,774)
Total equity	(12,077,240)	(9,084,774)
Total liabilities and equity	$ (13,216,151)	$ (11,231,428)