Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 196,567	$ 264,093	$ 233,752	$ 254,530
Short-term investments	35,476	31,109
Accounts receivable, net	582,787	508,355
Inventory, net	108,141	103,595
Assets held for sale	78,407	76,668
Other current assets	172,790	172,019
Total current assets	1,174,168	1,155,839
Property, plant and equipment, net	6,142,216	6,267,583
Goodwill	167,246	166,917
Deferred tax assets	409,671	366,586
Other long-term assets	199,157	230,090
Total assets	8,092,458	8,187,015
Current liabilities:
Less: current portion	124	297
Trade accounts payable	261,115	264,578
Accrued liabilities	592,060	543,248
Income taxes payable	23,268	13,811
Total current liabilities	876,567	821,934
Long-term debt	3,740,248	3,578,335
Other long-term liabilities	390,501	522,456
Deferred income taxes	12,364	9,495
Total liabilities	5,019,680	4,932,220
Shareholders' equity	3,049,235	3,247,025
Noncontrolling interest	23,543	7,770
Total equity	3,072,778	3,254,795	3,722,698	4,293,868
Total liabilities and equity	8,092,458	8,187,015
Reportable Legal Entities | Parent Company
Current assets:
Cash and cash equivalents	2,435	1,148	5,598	873
Other current assets	50	50
Total current assets	2,485	1,198
Intercompany receivables	146,431	142,447
Investment in consolidated affiliates	2,920,699	3,170,254
Total assets	3,069,615	3,313,899
Current liabilities:
Trade accounts payable	130	205
Accrued liabilities	20,250	20,669
Total current liabilities	20,380	20,874
Intercompany payable		46,000
Total liabilities	20,380	66,874
Shareholders' equity	3,049,235	3,247,025
Total equity	3,049,235	3,247,025
Total liabilities and equity	3,069,615	3,313,899
Reportable Legal Entities | Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	16	10,177	11	10
Other current assets	28,099	22,209
Total current assets	28,115	32,386
Investment in consolidated affiliates	7,555,645	4,830,572
Deferred tax assets	493,576	443,049
Other long-term assets	114	344
Total assets	8,077,450	5,306,351
Current liabilities:
Trade accounts payable	49	8
Accrued liabilities	70,670	65,246
Total current liabilities	70,719	65,254
Long-term debt	3,812,391	3,796,550
Other long-term liabilities	22,800	22,659
Intercompany payable	1,185,322	1,439,390
Total liabilities	5,091,232	5,323,853
Shareholders' equity	2,986,218	(17,502)
Total equity	2,986,218	(17,502)
Total liabilities and equity	8,077,450	5,306,351
Reportable Legal Entities | Other Subsidiaries (Non-Guarantors)
Current assets:
Cash and cash equivalents	194,116	252,768	$ 228,143	$ 253,647
Short-term investments	35,476	31,109
Accounts receivable, net	582,787	508,355
Inventory, net	108,141	103,595
Assets held for sale	78,407	76,668
Other current assets	144,641	149,760
Total current assets	1,143,568	1,122,255
Property, plant and equipment, net	6,142,216	6,267,583
Goodwill	167,246	166,917
Intercompany receivables	1,038,891	1,342,942
Investment in consolidated affiliates	4,545,780	1,083,948
Deferred tax assets	409,671	366,586
Other long-term assets	271,186	447,962
Total assets	13,718,558	10,798,193
Current liabilities:
Less: current portion	124	297
Trade accounts payable	260,936	264,365
Accrued liabilities	501,140	457,333
Income taxes payable	23,268	13,811
Total current liabilities	785,468	735,806
Other long-term liabilities	367,701	499,797
Deferred income taxes	505,940	452,544
Total liabilities	1,659,109	1,688,147
Shareholders' equity	12,035,906	9,102,276
Noncontrolling interest	23,543	7,770
Total equity	12,059,449	9,110,046
Total liabilities and equity	13,718,558	10,798,193
Consolidating Adjustments
Current assets:
Intercompany receivables	(1,185,322)	(1,485,389)
Investment in consolidated affiliates	(15,022,124)	(9,084,774)
Deferred tax assets	(493,576)	(443,049)
Other long-term assets	(72,143)	(218,216)
Total assets	(16,773,165)	(11,231,428)
Current liabilities:
Long-term debt	(72,143)	(218,215)
Deferred income taxes	(493,576)	(443,049)
Intercompany payable	(1,185,322)	(1,485,390)
Total liabilities	(1,751,041)	(2,146,654)
Shareholders' equity	(15,022,124)	(9,084,774)
Total equity	(15,022,124)	(9,084,774)
Total liabilities and equity	$ (16,773,165)	$ (11,231,428)