Related Party Transactions (Schedule Of Related Party Transactions) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Net trading	$ 31,026	$ 28,056	$ 38,528
Income / (loss) from equity method affiliates		27	1,828
Professional fees and other operating	8,504	9,062	13,410
TBBK [Member]
Related Party Transaction [Line Items]
Net trading		24	483
Star Asia [Member]
Related Party Transaction [Line Items]
Management fee revenue		125	2,329
Principal transactions and other income, Gain/(Loss)			(13,065)
Star Asia Manager [Member]
Related Party Transaction [Line Items]
Income / (loss) from equity method affiliates			158
Star Asia SPV [Member]
Related Party Transaction [Line Items]
Income / (loss) from equity method affiliates			1,287
Star Asia Opportunity [Member]
Related Party Transaction [Line Items]
Income / (loss) from equity method affiliates			(5)
Star Asia Capital Management [Member]
Related Party Transaction [Line Items]
Income / (loss) from equity method affiliates		13	145
Star Asia Special Situations Fund [Member]
Related Party Transaction [Line Items]
Principal transactions and other income, Gain/(Loss)			152
S.A.A. Manager [Member]
Related Party Transaction [Line Items]
Income / (loss) from equity method affiliates		14	255
EuroDekania [Member]
Related Party Transaction [Line Items]
Principal transactions and other income, Gain/(Loss)			1,971
Deep Value [Member]
Related Party Transaction [Line Items]
Income / (loss) from equity method affiliates			(13)
E.B.C. [Member]
Related Party Transaction [Line Items]
Interest expense incurred	228	224	59
Edward E. Cohen IRA [Member]
Related Party Transaction [Line Items]
Interest expense incurred	210
Mead Park Capital [Member]
Related Party Transaction [Line Items]
Interest expense incurred	340	547	144
Mead Park Advisors LLC [Member]
Related Party Transaction [Line Items]
Professional fees and other operating	200
Resource America [Member]
Related Party Transaction [Line Items]
Net trading	3
Woodlea [Member]
Related Party Transaction [Line Items]
Professional fees and other operating	39
Other Related Parties [Member]
Related Party Transaction [Line Items]
Income / (loss) from equity method affiliates			1
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Management fee revenue		125	2,329
Net trading	3	24	483
Principal transactions and other income, Gain/(Loss)			(10,942)
Income / (loss) from equity method affiliates		27	1,828
Professional fees and other operating	239
Interest expense incurred	$ 778	$ 771	$ 203