Business Segment Information (Schedule Of Financial Information About Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenues	$ 372,331	$ 343,831	$ 732,315	$ 678,094
Expenses	259,372	236,456	511,234	470,860
Operating profit (loss)	112,959	107,375	221,081	207,234
Gain on sale of subsidiary	0	0	0	2,791
Segment profit (loss)	112,959	107,375	221,081	210,025
Private Banks [Member]
Segment Reporting Information [Line Items]
Revenues	116,184	114,836	228,818	228,197
Expenses	112,353	102,862	220,903	206,603
Operating profit (loss)	3,831	11,974	7,915	21,594
Gain on sale of subsidiary	0	0	0	2,791
Segment profit (loss)	3,831	11,974	7,915	24,385
Investment Advisors [Member]
Segment Reporting Information [Line Items]
Revenues	92,746	81,883	180,984	158,562
Expenses	49,380	44,721	96,919	89,495
Operating profit (loss)	43,366	37,162	84,065	69,067
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	43,366	37,162	84,065	69,067
Institutional Investors [Member]
Segment Reporting Information [Line Items]
Revenues	78,068	74,674	155,072	147,571
Expenses	38,668	36,550	77,496	71,932
Operating profit (loss)	39,400	38,124	77,576	75,639
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	39,400	38,124	77,576	75,639
Investment Managers [Member]
Segment Reporting Information [Line Items]
Revenues	83,616	70,938	164,103	140,856
Expenses	53,847	46,968	105,912	92,243
Operating profit (loss)	29,769	23,970	58,191	48,613
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	29,769	23,970	58,191	48,613
Investments In New Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	1,717	1,500	3,338	2,908
Expenses	5,124	5,355	10,004	10,587
Operating profit (loss)	(3,407)	(3,855)	(6,666)	(7,679)
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	$ (3,407)	$ (3,855)	$ (6,666)	$ (7,679)

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- Definition

Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2443-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2941-110230

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Excludes Selling, General and Administrative Expense.

+ References

No definition available.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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+ References

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