Segment Reporting (Schedule of Information of Total Assets on Segment Basis) (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Total assets	$ 4,513,608	$ 4,213,115
Global Wealth Management [Member]
Total assets	3,264,594	2,965,168
Institutional Group [Member]
Total assets	907,471	883,235
Other [Member]
Total assets	$ 341,543	$ 364,712