Business Changes And Developments (Intangible Assets Associated With Company's Acquisitions) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	$ 66,610	$ 62,569
Intangible assets, Accumulated Amortization	25,701	13,337
Investment Banking [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	19,780	14,559
Intangible assets, Accumulated Amortization	14,750	8,846
Investment Management [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	46,830	48,010
Intangible assets, Accumulated Amortization	10,951	4,491
Client Related [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	61,085	55,672
Intangible assets, Accumulated Amortization	24,071	11,332
Client Related [Member] | Investment Banking [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	17,835	11,242
Intangible assets, Accumulated Amortization	13,874	7,120
Client Related [Member] | Investment Management [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	43,250	44,430
Intangible assets, Accumulated Amortization	10,197	4,212
Professional Licenses [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount		275
Intangible assets, Accumulated Amortization		259
Professional Licenses [Member] | Investment Banking [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount		275
Intangible assets, Accumulated Amortization		259
Acquired Mandates [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	1,810	1,810
Intangible assets, Accumulated Amortization	836	384
Acquired Mandates [Member] | Investment Banking [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	1,810	1,810
Intangible assets, Accumulated Amortization	836	384
Non-Compete/Non-Solicit Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	1,915	2,298
Intangible assets, Accumulated Amortization	604	588
Non-Compete/Non-Solicit Agreements [Member] | Investment Banking [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	135	518
Intangible assets, Accumulated Amortization	40	380
Non-Compete/Non-Solicit Agreements [Member] | Investment Management [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	1,780	1,780
Intangible assets, Accumulated Amortization	564	208
Other [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	1,800	2,514
Intangible assets, Accumulated Amortization	190	774
Other [Member] | Investment Banking [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount		714
Intangible assets, Accumulated Amortization		703
Other [Member] | Investment Management [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	1,800	1,800
Intangible assets, Accumulated Amortization	$ 190	$ 71