Derivative Activities (Gains (Losses) Of Derivative Contacts By Statement Of Operations Location) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instrument	$ (4,130)		$ 42,850		$ 18,434
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instrument	(1,217)	[1]	53,071	[1]	47,860	[1]
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instrument	$ (2,913)		$ (10,221)		$ (29,426)

[1] Gain (loss) on commodity derivative contracts is located in other income (expense) in the consolidated statements of operations.