Receivables From And Payables To Brokers, Dealers And Clearing Organizations (Amounts Payable To Brokers, Dealers, And Clearing Organizations) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Receivables From And Payables To Brokers, Dealers And Clearing Organizations [Abstract]
Deposits received for securities loaned	$ 169,283	$ 19,218
Payable to clearing organizations	23,112	9,246
Securities failed to receive	13,363	4,747
Payables to broker, dealers and clearing organizations, Total	$ 205,758	$ 33,211