Long-Term Debt (Schedule Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		1 Months Ended	12 Months Ended			12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jan. 31, 2006 6 5/8% Senior Notes Due 2016 [Member]	Dec. 31, 2011 6 5/8% Senior Notes Due 2016 [Member]	Dec. 31, 2010 6 5/8% Senior Notes Due 2016 [Member]	Jan. 13, 2006 6 5/8% Senior Notes Due 2016 [Member]	Dec. 31, 2011 GO Zone 6 1/2% Senior Notes Due 2029 [Member]	Dec. 31, 2010 GO Zone 6 1/2% Senior Notes Due 2029 [Member]	Dec. 31, 2011 GO Zone 6 3/4% Senior Notes Due 2032 [Member]	Dec. 31, 2010 GO Zone 6 3/4% Senior Notes Due 2032 [Member]	Dec. 31, 2011 GO Zone 6 1/2% Tax-Exempt Revenue Bonds Due 2035 [Member]	Dec. 31, 2010 GO Zone 6 1/2% Tax-Exempt Revenue Bonds Due 2035 [Member]	Dec. 31, 2011 IKE Zone 6 1/2% Tax-Exempt Revenue Bonds Due 2035 [Member]	Dec. 31, 2010 IKE Zone 6 1/2% Tax-Exempt Revenue Bonds Due 2035 [Member]	Dec. 31, 1997 Waste Disposal Revenue Bonds Due 2027 [Member]	Dec. 31, 2011 Waste Disposal Revenue Bonds Due 2027 [Member]	Dec. 31, 2010 Waste Disposal Revenue Bonds Due 2027 [Member]
Debt Instrument [Line Items]
Senior notes				$ 249,674	$ 249,593		$ 100,000	$ 100,000	$ 250,000	$ 250,000	$ 89,000	$ 89,000	$ 65,000	$ 65,000
Non-current loan payable																10,889	10,889
Long-term debt	$ 764,563	$ 764,482
Stated interest rate				6.625%	6.625%	6.625%	6.50%	6.50%	6.75%	6.75%	6.50%	6.50%	6.50%	6.50%
Maturity	2016		2016	2016			2029		2032		2035		2035		December 2027	2027