Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 177,043	$ 254,530	$ 251,366	$ 501,149
Short-term investments	23,607	20,059
Assets held for sale	69,436	75,678
Accounts receivable, net	503,966	784,671
Inventory	141,934	153,824
Other current assets	156,094	187,135
Total current assets	1,072,080	1,475,897
Property, plant and equipment, net	6,616,711	7,027,802
Goodwill	167,131	166,659
Investment in unconsolidated affiliates	889	415,177
Other long-term assets	567,693	452,305
Total assets	8,424,504	9,537,840
Current liabilities:
Current portion of debt	120	6,508
Trade accounts payable	215,627	271,984
Accrued liabilities	548,337	686,613
Income taxes payable	23,778	41,394
Total current liabilities	787,862	1,006,499
Long-term debt	3,475,978	3,655,200
Other long-term liabilities	551,004	552,947
Deferred income taxes	10,966	29,326
Total liabilities	4,825,810	5,243,972
Shareholders' equity	3,591,929	4,282,710
Noncontrolling interest	6,765	11,158
Total equity	3,598,694	4,293,868	4,511,399	4,918,789
Total liabilities and equity	8,424,504	9,537,840
Reportable Legal Entities | Parent Company
Current assets:
Cash and cash equivalents	1,055	873	820	1,170
Other current assets	50	50
Total current assets	1,105	923
Intercompany receivables	136,195	139,366
Investment in consolidated affiliates	3,541,138	4,183,362
Total assets	3,678,438	4,323,651
Current liabilities:
Trade accounts payable	110	71
Accrued liabilities	20,399	370
Total current liabilities	20,509	441
Intercompany payable	66,000	40,500
Total liabilities	86,509	40,941
Shareholders' equity	3,591,929	4,282,710
Total equity	3,591,929	4,282,710
Total liabilities and equity	3,678,438	4,323,651
Reportable Legal Entities | Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	8	10	12	7
Other current assets	6,694	9,016
Total current assets	6,702	9,026
Intercompany receivables	11,000	11,000
Investment in consolidated affiliates	4,891,538	4,973,327
Deferred tax assets	423,166	366,818
Other long-term assets	413	12,907
Total assets	5,332,819	5,373,078
Current liabilities:
Trade accounts payable	114	3
Accrued liabilities	18,239	64,550
Total current liabilities	18,353	64,553
Long-term debt	3,693,248	3,723,138
Other long-term liabilities	22,606	35,086
Intercompany payable	1,523,396	1,370,176
Total liabilities	5,257,603	5,192,953
Shareholders' equity	75,216	180,125
Total equity	75,216	180,125
Total liabilities and equity	5,332,819	5,373,078
Reportable Legal Entities | Other Subsidiaries (Non-Guarantors)
Current assets:
Cash and cash equivalents	175,980	253,647	$ 250,534	$ 499,972
Short-term investments	23,607	20,059
Assets held for sale	69,436	75,678
Accounts receivable, net	503,966	784,671
Inventory	141,934	153,824
Other current assets	149,350	178,069
Total current assets	1,064,273	1,465,948
Property, plant and equipment, net	6,616,711	7,027,802
Goodwill	167,131	166,659
Intercompany receivables	1,442,201	1,260,310
Investment in consolidated affiliates	1,178,531	1,284,225
Investment in unconsolidated affiliates	889	415,177
Other long-term assets	784,550	507,336
Total assets	11,254,286	12,127,457
Current liabilities:
Current portion of debt	120	6,508
Trade accounts payable	215,403	271,910
Accrued liabilities	509,699	621,693
Income taxes payable	23,778	41,394
Total current liabilities	749,000	941,505
Other long-term liabilities	528,398	517,861
Deferred income taxes	434,132	396,144
Total liabilities	1,711,530	1,855,510
Shareholders' equity	9,535,991	10,260,789
Noncontrolling interest	6,765	11,158
Total equity	9,542,756	10,271,947
Total liabilities and equity	11,254,286	12,127,457
Consolidating Adjustments
Current assets:
Intercompany receivables	(1,589,396)	(1,410,676)
Investment in consolidated affiliates	(9,611,207)	(10,440,914)
Deferred tax assets	(423,166)	(366,818)
Other long-term assets	(217,270)	(67,938)
Total assets	(11,841,039)	(12,286,346)
Current liabilities:
Long-term debt	(217,270)	(67,938)
Deferred income taxes	(423,166)	(366,818)
Intercompany payable	(1,589,396)	(1,410,676)
Total liabilities	(2,229,832)	(1,845,432)
Shareholders' equity	(9,611,207)	(10,440,914)
Total equity	(9,611,207)	(10,440,914)
Total liabilities and equity	$ (11,841,039)	$ (12,286,346)