Interest Income And Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest Income Expense Net [Abstract]
Investment securities	$ 10,641	$ 16,976	$ 38,674	$ 54,500
Bank loans, net of unearned income	20,705	23,475	60,460	52,377
Margin balances	6,183	4,873	15,668	14,382
Other	5,847	6,772	15,162	19,776
Total interest income	43,376	52,096	129,964	141,035
Senior notes	5,408	7,831	19,364	18,158
Bank deposits	1,783	1,743	5,945	5,438
Other	2,605	1,654	7,605	5,105
Total interest expense	$ 9,796	$ 11,228	$ 32,914	$ 28,701