Business Changes and Developments Intangible Assets Associated with Acquisitions (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 103,279	$ 54,269
Intangible Assets, accumulated amortization	33,735	27,538
Client Related [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	93,630	48,130
Intangible Assets, accumulated amortization	31,116	23,858
Acquired Mandates [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross		1,810
Intangible Assets, accumulated amortization		1,786
Non Compete Non Solicit Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	2,084	2,084
Intangible Assets, accumulated amortization	1,830	1,408
Other Intangible Assets Associated With Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	7,565	2,245
Intangible Assets, accumulated amortization	789	486
Investment Banking [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	53,255	4,245
Intangible Assets, accumulated amortization	4,254	3,179
Investment Banking [Member] | Client Related [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	47,800	2,300
Intangible Assets, accumulated amortization	4,006	1,299
Investment Banking [Member] | Acquired Mandates [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross		1,810
Intangible Assets, accumulated amortization		1,786
Investment Banking [Member] | Non Compete Non Solicit Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	135	135
Intangible Assets, accumulated amortization	121	94
Investment Banking [Member] | Other Intangible Assets Associated With Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	5,320	0
Intangible Assets, accumulated amortization	127	0
Investment Management [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	50,024	50,024
Intangible Assets, accumulated amortization	29,481	24,359
Investment Management [Member] | Client Related [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	45,830	45,830
Intangible Assets, accumulated amortization	27,110	22,559
Investment Management [Member] | Acquired Mandates [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross		0
Intangible Assets, accumulated amortization		0
Investment Management [Member] | Non Compete Non Solicit Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	1,949	1,949
Intangible Assets, accumulated amortization	1,709	1,314
Investment Management [Member] | Other Intangible Assets Associated With Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	2,245	2,245
Intangible Assets, accumulated amortization	$ 662	$ 486