Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statement Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed Income Statements, Captions [Line Items]
Total revenues	$ 151,355	$ 81,262
Total costs and expenses	111,334	392,536
Income (loss) before income taxes	40,021	(311,274)
Income tax (expense) benefit	0	(121)
Equity (deficit) in income of subsidiaries	0	0
Net Income (loss)	40,021	(311,395)
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	0	0
Total costs and expenses	10	376
Income (loss) before income taxes	(10)	(376)
Income tax (expense) benefit	0	(121)
Equity (deficit) in income of subsidiaries	(58,817)	281,101
Net Income (loss)	(58,827)	280,604
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	82	115
Total costs and expenses	18,868	29,912
Income (loss) before income taxes	(18,786)	(29,797)
Income tax (expense) benefit	0	0
Equity (deficit) in income of subsidiaries	58,817	(281,101)
Net Income (loss)	40,031	(310,898)
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	151,273	81,147
Total costs and expenses	92,456	362,248
Income (loss) before income taxes	58,817	(281,101)
Income tax (expense) benefit	0	0
Equity (deficit) in income of subsidiaries	0	0
Net Income (loss)	58,817	(281,101)
Combined Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	0	0
Total costs and expenses	0	0
Income (loss) before income taxes	0	0
Income tax (expense) benefit	0	0
Equity (deficit) in income of subsidiaries	0	0
Net Income (loss)	$ 0	$ 0