Derivative Financial Instruments (Schedule Of Marketing And Basis Transfer Derivative Contracts) (Details)	3 Months Ended
	Jun. 30, 2012
Average Daily Gas Production Associated with Marketing Derivatives (MMBtu) [Member]
Price Differential	0.25
Average Daily Gas Production Associated with Marketing Derivatives (MMBtu) [Member] | Basic Index Swaps [Member]
Index swap volume	26,739
Average Daily Gas Production Associated with Basis Transfer Derivatives (MMBtu) [Member]
NGI-So Cal Border Monthly price differential to NYMEX HH	0.12
IJ-HSC Price Differential To NYMEX HH	(0.05)
Average Daily Gas Production Associated with Basis Transfer Derivatives (MMBtu) [Member] | Basic Short Index Swaps [Member]
Index swap volume	3,343
Average Daily Gas Production Associated with Basis Transfer Derivatives (MMBtu) [Member] | Basic Long Index Swaps [Member]
Index swap volume	(3,343)