Derivative Financial Instruments (Derivatives And Hedging-Cash Flow Hedges) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCL on Derivative	$ 2,675	$ 4,613	$ 2,675	$ 4,613
Amount of Gain (Loss) Reclassified from AOCL into Income	41	41	82	82
Interest Rate Swap Agreements [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCL on Derivative	1,008		1,008
Amount of Gain (Loss) Reclassified from AOCL into Income	41	41	82	82
NYMEX Commodity Contracts [Member] | Product Sales Revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCL on Derivative	$ 1,667	$ 4,613	$ 1,667	$ 4,613