Debt (Grouping Of Debt Between Fixed And Variable As Well As Secured And Unsecured) (Details) (USD $) In Thousands	Jun. 30, 2011		Dec. 31, 2010
Debt, net	$ 2,615,976	[1]	$ 2,589,448	[1]
As To Interest Rate [Member]
Fixed-rate debt	2,289,738		2,349,802
Variable-rate debt	326,238		239,646
Debt, net	2,615,976		2,589,448
As To Collateralization [Member]
Debt, net	2,615,976		2,589,448
Unsecured debt	1,525,239		1,450,148
Secured debt	$ 1,090,737		$ 1,139,300

[1] Consolidated Variable Interest Entities' Assets and Liabilities included in the above balances (See Note 3):