Fair Value Measurements (Reconciliations Of Level 3 Fair Value Measurements) (Details) (Collar, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Collar
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Beginning of period	$ (2,595)		$ (595)
Included in earnings	6,108	[1]	(2,637)	[1]
Included in other comprehensive income (loss)	0		0
Settlements	(158)		637
End of period	3,355		(2,595)
Total gains (losses) for the period included in earnings attributable to the change in unrealized gain relating to assets still held at end of period	$ 5,950		$ (2,000)

[1] Commodity sales collars are reported in the consolidated statements of income in oil and gas revenues (for cash flow hedges), and gain (loss) on derivatives not designated as hedges and hedge ineffectiveness, net, respectively.