Debt (Schedule Of Debt) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2013		Dec. 31, 2012
Debt Instrument [Line Items]
Unsecured notes payable under credit facilities	$ 104,500		$ 66,000
Debt service guaranty liability	74,075		74,075
Obligations under capital leases	21,000		21,000
Total	2,350,762	[1]	2,204,030	[1]
Debt Payable To 2038 [Member]
Debt Instrument [Line Items]
Debt payable to 2038 at 2.6% to 8.6% in 2013 and 2.6% to 8.8% in 2012	2,150,132		2,041,709
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%		2.60%
Debt Payable To 2038 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt stated interest rate	8.60%		8.80%
Industrial Revenue Bonds Payable To 2015 [Member]
Debt Instrument [Line Items]
Industrial revenue bonds payable to 2015 at 2.4%	$ 1,055		$ 1,246
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 17):