Debt (Schedule Of Debt) (Details) - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Schedule of Long-term Debt, By Type [Line Items]
Debt payable, net to 2038	[1]	$ 1,899,540	$ 1,656,083
Unsecured notes payable under credit facilities		121,500	189,000
Debt service guaranty liability		72,105	72,105
Obligations under capital leases		21,000	21,000
Total		$ 2,114,145	$ 1,938,188
Debt stated interest rate		3.50%	7.40%
Debt Payable To 2038 [Member] | Minimum [Member]
Schedule of Long-term Debt, By Type [Line Items]
Debt stated interest rate		1.70%	3.40%
Debt Payable To 2038 [Member] | Maximum [Member]
Schedule of Long-term Debt, By Type [Line Items]
Debt stated interest rate		8.60%	8.60%
Debt Payable To 2038 [Member] | Weighted Average [Member]
Schedule of Long-term Debt, By Type [Line Items]
Debt stated interest rate		4.30%	4.80%

[1] At September 30, 2015, interest rates ranged from 1.7% to 8.6% at a weighted average rate of 4.3%. At December 31, 2014, interest rates ranged from 3.4% to 8.6% at a weighted average rate of 4.8%.