Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment, Net [Abstract]
Land	$ 13,963	$ 13,509
Building and improvements	137,658	135,049
Plant and equipment	2,131,933	2,039,050
Other	161,761	147,342
Property, plant and equipment, gross	2,445,315	2,334,950
Less: Accumulated depreciation	(1,287,050)	(1,196,845)
Property, plant and equipment, net, before construction in progress	1,158,265	1,138,105
Construction in progress	351,783	93,961
Property, plant and equipment, net	$ 1,510,048	$ 1,232,066