Acquisitions (Narrative) (Details) (USD $)		12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2012 Miller Buckfire And Company L.L.C. [Member]	Dec. 31, 2012 East Shore Aircraft L.L.C. [Member] item	Dec. 31, 2012 Stone And Youngberg L.L.C. [Member]	Dec. 31, 2011 Stone And Youngberg L.L.C. [Member]	Mar. 31, 2012 U.B.S. Wealth Management, Americas [Member]	Dec. 31, 2009 U.B.S. Wealth Management, Americas [Member] store
Business Acquisition [Line Items]
Percentage of voting interests acquired	100.00%	100.00%
Purchase price		$ 112,900,000
Cash consideration	7,300,000			24,000,000
Initial investment in acquiree	28,000,000
Fair value of equity issued of issuable	21,700,000
Payment period of purchase consideration			3 years
Goodwill recorded in business combination	57,700,000
Contingent earn-out payments, maximum				25,000,000
Contingent earn-out payments, fair value			17,000,000	23,500,000		9,700,000
Contingent earn-out payments, period				5 years		2 years
Number of aircraft acquired		15
Number of branches acquired						56
Percentage of Acquiree lease payments used to pay interest on non-recourse debt		65.00%
Cash payments			$ 7,000,000		$ 9,200,000