Supplemental Guarantor Information (Consolidating Statements of Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$ (71,050)	$ (47,705)	$ (26,390)	$ (59,724)	$ (118,755)	$ (86,114)
Change in cumulative translation adjustment, net of tax	(1,916)	$ 1,073	(7,053)	$ 4,388	(843)	(2,665)
Comprehensive loss	(72,966)		(33,443)		(119,598)	(88,779)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	107,606		15,229		162,430	92,591
Change in cumulative translation adjustment, net of tax	3,832		14,106		1,686	5,330
Comprehensive loss	111,438		29,335		164,116	97,921
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	(71,050)		(26,390)		(118,755)	(86,114)
Change in cumulative translation adjustment, net of tax	(1,916)		(7,053)		(843)	(2,665)
Comprehensive loss	(72,966)		(33,443)		(119,598)	(88,779)
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	(71,050)		(26,390)		(118,755)	(86,114)
Change in cumulative translation adjustment, net of tax	(1,916)		(7,053)		(843)	(2,665)
Comprehensive loss	(72,966)		(33,443)		(119,598)	(88,779)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	(38,780)		16,429		(47,750)	11,245
Comprehensive loss	(38,780)		16,429		(47,750)	11,245
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	2,224		(5,268)		4,075	(17,722)
Change in cumulative translation adjustment, net of tax	(1,916)		(7,053)		(843)	(2,665)
Comprehensive loss	$ 308		$ (12,321)		$ 3,232	$ (20,387)