Variable Interest Entities (Summary Of Consolidated Variable Interest Entities) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) joint_venture	Dec. 31, 2015 USD ($)
Variable Interest Entity [Line Items]
Number of VIE's guaranteed by company | joint_venture	1
Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Assets Held by VIEs	$ 504,293	$ 289,558
Assets Held as Collateral for Debt	46,136	57,735
Maximum Risk of Loss (2)	$ 29,784	$ 37,178