Fair Value Disclosures (Summary Of Changes In Fair Value Of Financial Assets And Liabilities Classified As Level 3) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013
Total gains/losses (realized and unrealized)	$ 3,400
Total gains/losses (realized and unrealized)	400
Corporate Equity Securities [Member]
Beginning Balance	13,234	[1]
Total gains/losses (realized and unrealized)	2,906	[1],[2]
Purchases	5,023	[1]
Sales	(2,984)	[1]
Net transfers into/ (out of) Level 3	1,398	[1]
Ending Balance	19,577	[1]
Change in unrealized gains/(losses) relating to instruments still held	2,058	[1],[2]
Beginning Balance	38	[1]
Ending Balance	38	[1]
Corporate Debt Securities [Member]
Beginning Balance	31,820	[1]
Total gains/losses (realized and unrealized)	(2,867)	[1],[2]
Purchases	918	[1]
Sales	(11,989)	[1]
Net transfers into/ (out of) Level 3	733	[1]
Ending Balance	18,615	[1]
Change in unrealized gains/(losses) relating to instruments still held	(2,242)	[1],[2]
Collateralized Debt Obligations [Member]
Beginning Balance	29,776	[1]
Total gains/losses (realized and unrealized)	6,698	[1],[2]
Purchases	17,864	[1]
Sales	(6,270)	[1]
Net transfers into/ (out of) Level 3	(2,944)	[1]
Ending Balance	45,124	[1]
Change in unrealized gains/(losses) relating to instruments still held	6,148	[1],[2]
Residential Mortgage-Backed Securities [Member]
Beginning Balance	169,426	[1]
Total gains/losses (realized and unrealized)	(86)	[1],[2]
Purchases	57,750	[1]
Sales	(71,534)	[1]
Settlements	(5,436)	[1]
Net transfers into/ (out of) Level 3	(6,354)	[1]
Ending Balance	143,766	[1]
Change in unrealized gains/(losses) relating to instruments still held	(367)	[1],[2]
Beginning Balance	1,542	[1]
Purchases	(1,542)	[1]
Commercial Mortgage-Backed Securities [Member]
Beginning Balance	17,794	[1]
Total gains/losses (realized and unrealized)	(2,905)	[1],[2]
Purchases	1,403	[1]
Sales	(2,744)	[1]
Settlements	(1,578)	[1]
Net transfers into/ (out of) Level 3	4,098	[1]
Ending Balance	16,068	[1]
Change in unrealized gains/(losses) relating to instruments still held	(3,835)	[1],[2]
Other Asset-Backed Securities [Member]
Beginning Balance	1,252	[1]
Total gains/losses (realized and unrealized)	(4)	[1],[2]
Net transfers into/ (out of) Level 3	196	[1]
Ending Balance	1,444	[1]
Change in unrealized gains/(losses) relating to instruments still held	(4)	[1],[2]
Loans And Other Receivables [Member]
Beginning Balance	170,986	[1]
Total gains/losses (realized and unrealized)	(5,049)	[1],[2]
Purchases	160,409	[1]
Sales	(24,741)	[1]
Settlements	(188,268)	[1]
Net transfers into/ (out of) Level 3	4,159	[1]
Ending Balance	117,496	[1]
Change in unrealized gains/(losses) relating to instruments still held	(6,925)	[1],[2]
Investments At Fair Value [Member]
Beginning Balance	70,067	[1]
Total gains/losses (realized and unrealized)	(1,197)	[1],[2]
Purchases	5,000	[1]
Settlements	(2,493)	[1]
Net transfers into/ (out of) Level 3	4,987	[1]
Ending Balance	76,364	[1]
Change in unrealized gains/(losses) relating to instruments still held	(1,349)	[1],[2]
Investments in managed funds [Member]
Beginning Balance	59,976	[1]
Total gains/losses (realized and unrealized)	(927)	[1],[2]
Purchases	2,532	[1]
Settlements	(6,562)	[1]
Net transfers into/ (out of) Level 3	122	[1]
Ending Balance	55,141	[1]
Change in unrealized gains/(losses) relating to instruments still held	(926)	[1],[2]
Net Derivatives [Member]
Beginning Balance	11,185	[1],[3]
Total gains/losses (realized and unrealized)	(386)	[1],[2],[3]
Ending Balance	10,799	[1],[3]
Change in unrealized gains/(losses) relating to instruments still held	386	[1],[2],[3]
Loans [Member]
Beginning Balance	7,398	[1]
Purchases	(7,398)	[1]
Sales	15,212	[1]
Ending Balance	15,212	[1]
Other Secured Financings [Member]
Net transfers into/ (out of) Level 3	2,294	[1],[3]
Ending Balance	$ 2,294	[1],[3]

[1] There were no issuances during the three months ended June 30, 2013.

[2] Realized and unrealized gains (losses) are reported in Principal transactions in the Consolidated Statements of Operations.

[3] Net derivatives represent Trading assets - Derivatives and Trading liabilities - Derivatives.