Supplemental Guarantor Information (Condensed Consolidating Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 336,072	$ 356,585	$ 367,438	$ 365,274	$ 389,447	$ 378,400	$ 356,901	$ 354,109	$ 1,425,369	$ 1,478,857	$ 1,305,529
Cost or revenues (exclusive of depreciation, depletion, amortization and accretion)	223,570	231,927	229,532	240,053	248,394	245,832	235,679	240,583	925,082	970,488	889,809
Depreciation, depletion, amortization and accretion	43,741	45,104	51,271	56,343	65,478	69,338	67,862	75,761	196,459	278,439	326,856
General and administrative expenses									268,226	276,468	285,597
Reduction in value of assets		9,628	7,557		322,713				17,185	322,713	10,390
Income (loss) from operations									18,417	(369,251)	(207,123)
Other expense:
Interest income (expense), net									(98,312)	(99,477)	(101,455)
Other income (expense)									(2,484)	(1,678)	(3,299)
Loss from continuing operations before income taxes									(82,379)	(470,406)	(311,877)
Income taxes									(4,626)	(43,003)	(131,562)
Net loss from continuing operations	(6,162)	(20,506)	(18,441)	(32,644)	(317,014)	(23,436)	(33,817)	(53,136)	(77,753)	(427,403)	(180,315)
Loss from discontinued operations, net of income tax	(92,362)	(17,936)	(52,609)	(15,061)	(433,171)	1,620	7,427	(6,588)	(177,968)	(430,712)	(25,606)
Net loss	$ (98,524)	$ (38,442)	$ (71,050)	$ (47,705)	$ (750,185)	$ (21,816)	$ (26,390)	$ (59,724)	(255,721)	(858,115)	(205,921)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues									(25,287)	(31,255)	(15,701)
Cost or revenues (exclusive of depreciation, depletion, amortization and accretion)									(25,287)	(31,255)	(15,701)
Other expense:
Equity in losses of consolidated subsidiaries									360,156	1,566,060	283,279
Loss from continuing operations before income taxes									360,156	1,566,060	283,279
Net loss from continuing operations									360,156	1,566,060	283,279
Net loss									360,156	1,566,060	283,279
Parent [Member]
Other expense:
Equity in losses of consolidated subsidiaries									(255,721)	(858,115)	(205,921)
Loss from continuing operations before income taxes									(255,721)	(858,115)	(205,921)
Net loss from continuing operations									(255,721)	(858,115)	(205,921)
Net loss									(255,721)	(858,115)	(205,921)
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Cost or revenues (exclusive of depreciation, depletion, amortization and accretion)									(7,023)	(13,265)	(4,123)
Depreciation, depletion, amortization and accretion									3,682	3,945	4,149
General and administrative expenses									87,727	95,725	86,840
Income (loss) from operations									(84,386)	(86,405)	(86,866)
Other expense:
Interest income (expense), net									(103,397)	(103,594)	(105,585)
Intercompany interest income (expense)									(107)
Other income (expense)									(1,732)	71	(1,350)
Equity in losses of consolidated subsidiaries									(107,768)	(707,348)	(76,394)
Loss from continuing operations before income taxes									(297,390)	(897,276)	(270,195)
Income taxes									(41,669)	(39,161)	(64,274)
Net loss from continuing operations									(255,721)	(858,115)	(205,921)
Net loss									(255,721)	(858,115)	(205,921)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues									1,126,456	1,238,343	1,086,567
Cost or revenues (exclusive of depreciation, depletion, amortization and accretion)									730,473	823,908	733,600
Depreciation, depletion, amortization and accretion									154,424	229,565	271,853
General and administrative expenses									134,123	129,667	142,166
Reduction in value of assets									14,900	230,429	2,273
Income (loss) from operations									92,536	(175,226)	(63,325)
Other expense:
Interest income (expense), net									5,115	3,950	4,451
Other income (expense)									(759)	1,014	202
Equity in losses of consolidated subsidiaries									3,333	(597)	(964)
Loss from continuing operations before income taxes									100,225	(170,859)	(59,636)
Income taxes									47,771	(4,124)	(59,169)
Net loss from continuing operations									52,454	(166,735)	(467)
Loss from discontinued operations, net of income tax									(177,968)	(429,983)	(6,696)
Net loss									(125,514)	(596,718)	(7,163)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues									324,200	271,769	234,663
Cost or revenues (exclusive of depreciation, depletion, amortization and accretion)									226,919	191,100	176,033
Depreciation, depletion, amortization and accretion									38,353	44,929	50,854
General and administrative expenses									46,376	51,076	56,591
Reduction in value of assets									2,285	92,284	8,117
Income (loss) from operations									10,267	(107,620)	(56,932)
Other expense:
Interest income (expense), net									(30)	167	(321)
Intercompany interest income (expense)									107
Other income (expense)									7	(2,763)	(2,151)
Loss from continuing operations before income taxes									10,351	(110,216)	(59,404)
Income taxes									(10,728)	282	(8,119)
Net loss from continuing operations									21,079	(110,498)	(51,285)
Loss from discontinued operations, net of income tax										(729)	(18,910)
Net loss									$ 21,079	$ (111,227)	$ (70,195)