Supplemental Guarantor Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 158,050	$ 172,000
Accounts receivable, net	447,353	398,056
Income taxes receivable		959
Other current assets	167,502	176,160
Assets held for sale		13,644
Total current assets	772,905	760,819
Property, plant and equipment, net	1,109,126	1,316,944
Goodwill	136,788	807,860	$ 803,917
Notes receivable	63,993	60,149
Restricted cash	5,698	20,483
Intangible and other long-term assets, net	127,452	143,970
Total assets	2,215,962	3,110,225	3,470,255
Current liabilities:
Accounts payable	139,325	119,716
Accrued expenses	219,180	221,757
Income taxes payable	734
Current portion of decommissioning liabilities	3,538	27,261
Liabilities held for sale		6,463
Total current liabilities	362,777	375,197
Deferred income taxes		61,058
Decommissioning liabilities	126,558	103,136
Long-term debt, net	1,282,921	1,279,771
Other long-term liabilities	152,967	158,634
Total stockholders' equity	290,739	1,132,429	$ 1,303,920	$ 2,210,812
Total liabilities and stockholders' equity	2,215,962	3,110,225
Eliminations [Member]
Current assets:
Accounts receivable, net		(5,235)
Intercompany accounts receivable	(90,674)	(70,700)
Total current assets	(90,674)	(75,935)
Long term intercompany accounts receivable	(4,417,627)	(4,431,595)
Equity investments of consolidated subsidiaries	(1,808,232)	(3,399,556)
Total assets	(6,316,533)	(7,907,086)
Current liabilities:
Accounts payable		(5,235)
Intercompany accounts payable	(90,674)	(70,700)
Total current liabilities	(90,674)	(75,935)
Long-term intercompany accounts payable	(4,417,627)	(4,431,595)
Total stockholders' equity	(1,808,232)	(3,399,556)
Total liabilities and stockholders' equity	(6,316,533)	(7,907,086)
Parent [Member]
Current assets:
Long term intercompany accounts receivable	2,243,431	2,221,697
Equity investments of consolidated subsidiaries	(1,952,647)	(1,088,736)
Total assets	290,784	1,132,961
Current liabilities:
Accrued expenses	45	532
Total current liabilities	45	532
Total stockholders' equity	290,739	1,132,429
Total liabilities and stockholders' equity	290,784	1,132,961
Issuer [Member]
Current assets:
Cash and cash equivalents	102,224	126,533
Accounts receivable, net	160
Intercompany accounts receivable	12,279	6,460
Other current assets	12,805	11,895
Total current assets	127,468	144,888
Property, plant and equipment, net	10,129	12,055
Equity investments of consolidated subsidiaries	3,754,887	4,481,702
Intangible and other long-term assets, net	19,255	22,118
Total assets	3,911,739	4,660,763
Current liabilities:
Accounts payable	8,807	14,339
Accrued expenses	102,845	116,767
Income taxes payable	1,237
Intercompany accounts payable	724	724
Total current liabilities	113,613	131,830
Deferred income taxes		(147,116)
Long-term debt, net	1,282,921	1,279,771
Long-term intercompany accounts payable	4,417,627	4,431,595
Other long-term liabilities	50,225	53,419
Total stockholders' equity	(1,952,647)	(1,088,736)
Total liabilities and stockholders' equity	3,911,739	4,660,763
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	707	440
Accounts receivable, net	367,497	332,402
Income taxes receivable		(221)
Intercompany accounts receivable	74,906	58,375
Other current assets	111,560	129,970
Total current assets	554,670	520,966
Property, plant and equipment, net	920,978	1,093,446
Goodwill	80,544	657,099
Notes receivable	63,993	60,149
Long term intercompany accounts receivable	1,991,912	2,032,056
Equity investments of consolidated subsidiaries	5,992	6,590
Restricted cash	5,653	20,483
Intangible and other long-term assets, net	100,847	113,632
Total assets	3,724,589	4,504,421
Current liabilities:
Accounts payable	109,903	89,714
Accrued expenses	86,926	80,825
Intercompany accounts payable	6,869	7,918
Current portion of decommissioning liabilities		25,670
Total current liabilities	203,698	204,127
Deferred income taxes		205,386
Decommissioning liabilities	126,558	101,293
Other long-term liabilities	76,543	79,061
Total stockholders' equity	3,317,790	3,914,554
Total liabilities and stockholders' equity	3,724,589	4,504,421
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	55,119	45,027
Accounts receivable, net	79,696	70,889
Income taxes receivable		1,180
Intercompany accounts receivable	3,489	5,865
Other current assets	43,137	34,295
Assets held for sale		13,644
Total current assets	181,441	170,900
Property, plant and equipment, net	178,019	211,443
Goodwill	56,244	150,761
Long term intercompany accounts receivable	182,284	177,842
Restricted cash	45
Intangible and other long-term assets, net	7,350	8,220
Total assets	605,383	719,166
Current liabilities:
Accounts payable	20,615	20,898
Accrued expenses	29,364	23,633
Income taxes payable	(503)
Intercompany accounts payable	83,081	62,058
Current portion of decommissioning liabilities	3,538	1,591
Liabilities held for sale		6,463
Total current liabilities	136,095	114,643
Deferred income taxes		2,788
Decommissioning liabilities		1,843
Other long-term liabilities	26,199	26,154
Total stockholders' equity	443,089	573,738
Total liabilities and stockholders' equity	$ 605,383	$ 719,166