Supplemental Guarantor Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 272,624	$ 158,050
Accounts receivable, net	332,047	447,353
Income taxes receivable	740
Other current assets	166,761	167,502
Assets held for sale	216,197
Total current assets	988,369	772,905
Property, plant and equipment, net	664,949	1,109,126
Operating lease right-of-use assets	80,906
Goodwill	137,695	136,788	$ 807,860
Notes receivable	68,092	63,993
Restricted cash	2,764	5,698
Intangible and other long-term assets, net	50,455	127,452
Total assets	1,993,230	2,215,962	3,110,225
Current liabilities:
Accounts payable	92,966	139,325
Accrued expenses	182,934	219,180
Income taxes payable		734
Current portion of decommissioning liabilities	3,649	3,538
Liabilities held for sale	44,938
Total current liabilities	324,487	362,777
Long-term debt, net	1,286,629	1,282,921
Deferred income taxes	3,247
Decommissioning liabilities	132,632	126,558
Operating lease liabilities	62,354
Other long-term liabilities	134,308	152,967
Total stockholders' equity	49,573	290,739	$ 1,132,429	$ 1,303,920
Total liabilities and stockholders' equity	1,993,230	2,215,962
Eliminations [Member]
Current assets:
Intercompany accounts receivable		(90,674)
Total current assets		(90,674)
Long term intercompany accounts receivable	(6,765,302)	(4,417,627)
Intercompany notes receivable	(9,400)
Equity investments of consolidated subsidiaries	(1,301,934)	(1,808,232)
Total assets	(8,076,636)	(6,316,533)
Current liabilities:
Intercompany accounts payable		(90,674)
Total current liabilities		(90,674)
Long-term intercompany accounts payable	(6,765,302)	(4,417,627)
Intercompany notes payable	(9,400)
Total stockholders' equity	(1,301,934)	(1,808,232)
Total liabilities and stockholders' equity	(8,076,636)	(6,316,533)
Parent [Member]
Current assets:
Long term intercompany accounts receivable	2,260,980	2,243,431
Equity investments of consolidated subsidiaries	(2,207,117)	(1,952,647)
Total assets	53,863	290,784
Current liabilities:
Accrued expenses		45
Total current liabilities		45
Long-term intercompany accounts payable	4,290
Total stockholders' equity	49,573	290,739
Total liabilities and stockholders' equity	53,863	290,784
Issuer [Member]
Current assets:
Cash and cash equivalents	210,691	102,224
Accounts receivable, net	750	160
Income taxes receivable	(1,080)
Intercompany accounts receivable		12,279
Other current assets	9,594	12,805
Total current assets	219,955	127,468
Property, plant and equipment, net	11,129	10,129
Operating lease right-of-use assets	22,052
Long term intercompany accounts receivable	1,281,183
Equity investments of consolidated subsidiaries	3,498,602	3,754,887
Intangible and other long-term assets, net	19,466	19,255
Total assets	5,052,387	3,911,739
Current liabilities:
Accounts payable	10,701	8,807
Accrued expenses	76,249	102,845
Income taxes payable		1,237
Intercompany accounts payable		724
Total current liabilities	86,950	113,613
Long-term debt, net	1,286,629	1,282,921
Deferred income taxes	3,247
Operating lease liabilities	22,738
Long-term intercompany accounts payable	5,805,516	4,417,627
Intercompany notes payable	9,400
Other long-term liabilities	45,024	50,225
Total stockholders' equity	(2,207,117)	(1,952,647)
Total liabilities and stockholders' equity	5,052,387	3,911,739
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	612	707
Accounts receivable, net	245,941	367,497
Intercompany accounts receivable		74,906
Other current assets	106,857	111,560
Assets held for sale	216,197
Total current assets	569,607	554,670
Property, plant and equipment, net	497,395	920,978
Operating lease right-of-use assets	44,048
Goodwill	80,544	80,544
Notes receivable	68,092	63,993
Long term intercompany accounts receivable	3,020,808	1,991,912
Equity investments of consolidated subsidiaries	10,449	5,992
Restricted cash	2,719	5,653
Intangible and other long-term assets, net	24,313	100,847
Total assets	4,317,975	3,724,589
Current liabilities:
Accounts payable	49,159	109,903
Accrued expenses	80,696	86,926
Intercompany accounts payable		6,869
Liabilities held for sale	44,938
Total current liabilities	174,793	203,698
Decommissioning liabilities	132,632	126,558
Operating lease liabilities	29,206
Long-term intercompany accounts payable	832,407
Other long-term liabilities	75,976	76,543
Total stockholders' equity	3,072,961	3,317,790
Total liabilities and stockholders' equity	4,317,975	3,724,589
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	61,321	55,119
Accounts receivable, net	85,356	79,696
Income taxes receivable	1,820
Intercompany accounts receivable		3,489
Other current assets	50,310	43,137
Total current assets	198,807	181,441
Property, plant and equipment, net	156,425	178,019
Operating lease right-of-use assets	14,806
Goodwill	57,151	56,244
Long term intercompany accounts receivable	202,331	182,284
Intercompany notes receivable	9,400
Restricted cash	45	45
Intangible and other long-term assets, net	6,676	7,350
Total assets	645,641	605,383
Current liabilities:
Accounts payable	33,106	20,615
Accrued expenses	25,989	29,364
Income taxes payable		(503)
Intercompany accounts payable		83,081
Current portion of decommissioning liabilities	3,649	3,538
Total current liabilities	62,744	136,095
Operating lease liabilities	10,410
Long-term intercompany accounts payable	123,089
Other long-term liabilities	13,308	26,199
Total stockholders' equity	436,090	443,089
Total liabilities and stockholders' equity	$ 645,641	$ 605,383