Derivative Instruments And Hedging Activities (Impact Of Derivative Instruments On Accumulated Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ (3,593)	$ 12,680	$ (10,831)	$ (1,122)
Oil And Natural Gas Commodity Contracts [Member]
Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)		12,759		(796)
Interest Rate Swaps [Member]
Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)		(79)		(326)
Foreign Exchange Contracts [Member]
Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ (3,593)		$ (10,831)