Other Assets (Schedule Of Other Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010
Other Assets [Line Items]
Goodwill, Cost	$ 29,990	$ 29,990
Goodwill, Accumulated Amortization
Goodwill, Net	29,990	29,990
Other intangible assets, Cost	1,161	1,161
Other intangible assets, Accumulated Amortization
Other intangible assets, Net	1,161	1,161
Cost	262,484	226,321
Accumulated Amortization	(126,909)	(115,073)
Net	135,575	111,248
Intangible Assets [Member]
Other Assets [Line Items]
Cost	100,130	100,065
Accumulated Amortization	(51,067)	(47,962)
Net	49,063	52,103
Available-For-Sale Investments [Member]
Other Assets [Line Items]
Cost	30,113
Accumulated Amortization
Net	30,113
Notes Receivable From Affiliate [Member]
Other Assets [Line Items]
Cost	2,383	3,575
Accumulated Amortization
Net	2,383	3,575
Turnaround Costs [Member]
Other Assets [Line Items]
Cost	86,728	85,307
Accumulated Amortization	(57,175)	(49,864)
Net	29,553	35,443
Intangible asset, Weighted Average Life (in years)	5
Debt Issuance Costs [Member]
Other Assets [Line Items]
Cost	20,628	17,930
Accumulated Amortization	(8,989)	(7,307)
Net	11,639	10,623
Intangible asset, Weighted Average Life (in years)	10
Other, Net [Member]
Other Assets [Line Items]
Cost	22,502	19,444
Accumulated Amortization	(9,678)	(9,940)
Net	12,824	9,504
Intangible asset, Weighted Average Life (in years)	5
Technology Licenses [Member]
Other Assets [Line Items]
Intangible assets, Cost	44,827	44,762
Intangible assets, Accumulated Amortization	(40,860)	(39,763)
Intangible assets, Net	3,967	4,999
Intangible asset, Weighted Average Life (in years)	12
Patents [Member]
Other Assets [Line Items]
Intangible assets, Cost	6,503	6,503
Intangible assets, Accumulated Amortization	(3,306)	(2,655)
Intangible assets, Net	3,197	3,848
Intangible asset, Weighted Average Life (in years)	10
Customer Relationships [Member]
Other Assets [Line Items]
Intangible assets, Cost	17,649	17,649
Intangible assets, Accumulated Amortization	(6,901)	(5,544)
Intangible assets, Net	$ 10,748	$ 12,105
Intangible asset, Weighted Average Life (in years)	13