Fair Value Measurements (Reconciliations Of Level 3 Fair Value Measurements) (Details) - Level 3 [Member] - USD ($) $ in Thousands		2 Months Ended	8 Months Ended
		Aug. 31, 2020	Aug. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Beginning of period		$ 843	$ 1,204
Included in earnings	[1]	(405)	872
Settlements		(438)	(2,076)
End of period		0	0
Total losses for the period included in earnings attributable to the change in unrealized gain (loss) relating to assets still held at end of period		$ (843)	$ (1,204)

[1] Commodity derivative activity is reported in the unaudited condensed consolidated statements of operations in gain (loss) on derivatives.