Condensed Consolidating Financial Information (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 254,530	$ 501,149	$ 389,915	$ 524,922
Short-term investments	20,059	35,020
Assets held for sale	75,678	146,467
Accounts receivable, net	784,671	1,517,503
Inventory	153,824	230,067
Deferred income taxes		118,230
Other current assets	187,135	193,438
Total current assets	1,475,897	2,741,874
Property, plant and equipment, net	7,027,802	8,599,125	8,597,813
Goodwill	166,659	173,928	512,964
Investment in unconsolidated affiliates	415,177	58,251
Other long-term assets	452,305	289,745
Total assets	9,537,840	11,862,923
Current liabilities:
Current portion of debt	6,508	6,190
Trade accounts payable	271,984	780,060
Accrued liabilities	686,613	728,004
Income taxes payable	41,394	53,221
Total current liabilities	1,006,499	1,567,475
Long-term debt	3,655,200	4,331,840
Other long-term liabilities	552,947	601,816
Deferred income taxes	29,326	443,003
Total liabilities	5,243,972	6,944,134
Shareholders' equity	4,282,710	4,908,619
Noncontrolling interest	11,158	10,170
Total equity	4,293,868	4,918,789	5,981,177	5,957,117
Total liabilities and equity	9,537,840	11,862,923
Reportable Legal Entities | Parent Company
Current assets:
Cash and cash equivalents	873	1,170	730	1,639
Other current assets	50	50
Total current assets	923	1,220
Intercompany receivables	139,366	136,360
Investment in consolidated affiliates	4,183,362	4,771,413
Total assets	4,323,651	4,908,993
Current liabilities:
Trade accounts payable	71	111
Accrued liabilities	370	263
Total current liabilities	441	374
Intercompany payable	40,500
Total liabilities	40,941	374
Shareholders' equity	4,282,710	4,908,619
Total equity	4,282,710	4,908,619
Total liabilities and equity	4,323,651	4,908,993
Reportable Legal Entities | Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	10	7	7,029	106,778
Other current assets	9,016	5,242
Short-term intercompany note		880,820
Total current assets	9,026	886,069
Property, plant and equipment, net		30,330
Intercompany receivables	11,000
Investment in consolidated affiliates	4,973,327	5,014,743
Deferred tax assets	366,818	294,655
Other long-term assets	12,907	13,279
Total assets	5,373,078	6,239,076
Current liabilities:
Trade accounts payable	3	2
Accrued liabilities	64,550	64,390
Total current liabilities	64,553	64,392
Long-term debt	3,723,138	4,372,280
Other long-term liabilities	35,086	35,480
Intercompany payable	1,370,176	1,422,882
Total liabilities	5,192,953	5,895,034
Shareholders' equity	180,125	344,042
Total equity	180,125	344,042
Total liabilities and equity	5,373,078	6,239,076
Reportable Legal Entities | Other Subsidiaries (Non-Guarantors)
Current assets:
Cash and cash equivalents	253,647	499,972	$ 382,156	$ 416,505
Short-term investments	20,059	35,020
Assets held for sale	75,678	146,467
Accounts receivable, net	784,671	1,517,503
Inventory	153,824	230,067
Deferred income taxes		118,230
Other current assets	178,069	188,146
Total current assets	1,465,948	2,735,405
Property, plant and equipment, net	7,027,802	8,568,795
Goodwill	166,659	173,928
Intercompany receivables	1,260,310	1,286,522
Investment in consolidated affiliates	1,284,225	1,448,688
Investment in unconsolidated affiliates	415,177	58,251
Other long-term assets	507,336	316,906
Total assets	12,127,457	14,588,495
Current liabilities:
Current portion of debt	6,508	6,190
Trade accounts payable	271,910	779,947
Accrued liabilities	621,693	663,351
Income taxes payable	41,394	53,221
Short-term intercompany note		880,820
Total current liabilities	941,505	2,383,529
Other long-term liabilities	517,861	566,336
Deferred income taxes	396,144	737,658
Total liabilities	1,855,510	3,687,523
Shareholders' equity	10,260,789	10,890,802
Noncontrolling interest	11,158	10,170
Total equity	10,271,947	10,900,972
Total liabilities and equity	12,127,457	14,588,495
Consolidating Adjustments
Current assets:
Short-term intercompany note		(880,820)
Total current assets		(880,820)
Intercompany receivables	(1,410,676)	(1,422,882)
Investment in consolidated affiliates	(10,440,914)	(11,234,844)
Deferred tax assets	(366,818)	(294,655)
Other long-term assets	(67,938)	(40,440)
Total assets	(12,286,346)	(13,873,641)
Current liabilities:
Short-term intercompany note		(880,820)
Total current liabilities		(880,820)
Long-term debt	(67,938)	(40,440)
Deferred income taxes	(366,818)	(294,655)
Intercompany payable	(1,410,676)	(1,422,882)
Total liabilities	(1,845,432)	(2,638,797)
Shareholders' equity	(10,440,914)	(11,234,844)
Total equity	(10,440,914)	(11,234,844)
Total liabilities and equity	$ (12,286,346)	$ (13,873,641)