Debt (Grouping Of Debt Between Fixed And Variable As Well As Secured And Unsecured) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Debt Instrument [Line Items]
Total	$ 2,350,762	[1]	$ 2,204,030	[1]
As To Interest Rate [Member]
Debt Instrument [Line Items]
Fixed-rate debt	2,103,023		1,992,599
Variable-rate debt	247,739		211,431
Total	2,350,762		2,204,030
As To Collateralization [Member]
Debt Instrument [Line Items]
Unsecured debt	1,540,756		1,270,742
Secured debt	810,006		933,288
Total	$ 2,350,762		$ 2,204,030

[1] Consolidated Variable Interest Entities’ Assets and Liabilities included in the above balances (See Note 17):