Fair Value Measurement (Summary Of Changes In Fair Value Of Level 3 Financial Assets And Financial Liabilities Held At Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Collateralized Debt Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 38,992	$ 76,325	$ 42,801	$ 47,503
Realized (losses) gains included in earnings	5,616	5,032	5,993	8,854
Purchases			0	25,000
Sales			(4,186)	0
Settlements	(8,264)	0	(8,264)	0
Ending Balance	36,344	81,357	36,344	81,357
The amount of total gains (losses) for the period included in earnings attributable to assets still held at September 30	5,616	5,032	6,510	8,854
Partnership Interest In Private Credit Fund [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	11,990	11,030	11,306	10,008
Realized (losses) gains included in earnings	134	(455)	818	567
Purchases			0	0
Sales			0	0
Settlements	0	0	0	0
Ending Balance	12,124	10,575	12,124	10,575
The amount of total gains (losses) for the period included in earnings attributable to assets still held at September 30	$ 134	$ (455)	$ 818	$ 567