Business Changes And Developments (Goodwill Associated With Company's Acquisitions) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 177,849	$ 139,031	$ 49,764
Acquisitions	44,366	88,230
Foreign Currency Translation	(5,548)	1,037
Goodwill, Ending Balance	177,849	139,031	49,764
Investment Banking [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	81,937	43,199	34,989
Acquisitions	44,286	7,173
Foreign Currency Translation	(5,548)	1,037
Goodwill, Ending Balance	81,937	43,199	34,989
Investment Management [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	95,912	95,832	14,775
Acquisitions	80	81,057
Goodwill, Ending Balance	$ 95,912	$ 95,832	$ 14,775

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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- Definition

Cumulative translation adjustment resulting from translating foreign currency financial statements into the reporting currency. Reported in equity as part of accumulated other comprehensive income.

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