Debt (Grouping Of Debt Between Fixed And Variable As Well As Secured And Unsecured) (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Schedule of Long-term Debt, By Type [Line Items]
Secured debt			$ 66,000
Total	[1]	$ 2,189,324	2,113,277
As To Interest Rate [Member]
Schedule of Long-term Debt, By Type [Line Items]
Fixed-rate debt		1,915,829	1,869,683
Variable-rate debt		273,495	243,594
Total		2,189,324	2,113,277
As To Collateralization [Member]
Schedule of Long-term Debt, By Type [Line Items]
Unsecured debt		1,681,507	1,650,521
Secured debt		507,817	462,756
Total		$ 2,189,324	$ 2,113,277

[1] * Consolidated variable interest entities' assets and debt included in the above balances (see Note 15):