Debt (Schedule Of Debt) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Debt Instrument [Line Items]
Unsecured notes payable under credit facilities	$ 66,000		$ 166,500
Debt service guaranty liability	74,075		74,075
Obligations under capital leases	21,000		21,000
Total	2,204,030	[1]	2,531,837	[1]
Debt Payable To 2038 [Member]
Debt Instrument [Line Items]
Debt payable to 2038 at 2.6% to 8.8% in 2012 and 1.5% to 8.8% in 2011	2,041,709		2,268,668
Debt maturity date	Dec. 23, 2038		Dec. 23, 2038
Debt Payable To 2038 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt stated interest rate	2.60%		1.50%
Debt Payable To 2038 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt stated interest rate	8.80%		8.80%
Industrial Revenue Bonds Payable To 2015 [Member]
Debt Instrument [Line Items]
Industrial revenue bonds payable to 2015 at 2.4%	$ 1,246		$ 1,594
Debt maturity date	Dec. 01, 2015		Dec. 01, 2015
Debt stated interest rate	2.40%		2.40%

[1] * Consolidated Variable Interest Entities' Assets and Liabilities included in the above balances (See Note 22):