Interest Income And Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Interest Income Expense Net [Abstract]
Investment securities	$ 13,618	$ 18,213	$ 28,372	$ 37,524
Bank loans, net of unearned income	20,952	15,294	39,937	28,902
Margin balances	5,123	4,843	9,485	9,509
Other	4,159	7,764	8,794	13,015
Total interest income	43,852	46,114	86,588	88,950
Senior notes	5,333	5,163	13,984	10,327
Bank deposits	2,047	1,950	4,162	3,695
Other	2,718	1,775	4,971	3,540
Total interest expense	$ 10,098	$ 8,888	$ 23,117	$ 17,562