Property And Equipment (Schedule Of Property And Equipment) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Oil and natural gas properties	$ 5,258,762	$ 3,923,154
Office furniture and fixtures	12,453	10,752
Building	11,550	5,398
Land	3,667	2,194
Total property and equipment	5,286,432	3,941,498
Accumulated depletion, depreciation, amortization and impairment	(1,896,413)	(1,050,879)
Property and equipment, net	$ 3,390,019	$ 2,890,619