Business Segment Information (Schedule Of Financial Information About Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Revenues	$ 386,018	$ 354,641	$ 1,118,333	$ 1,032,735
Expenses	271,288	241,482	782,522	712,342
Operating profit (loss)	114,730	113,159	335,811	320,393
Gain on sale of subsidiary	0	0	0	2,791
Segment profit (loss)	114,730	113,159	335,811	323,184
Private Banks [Member]
Segment Reporting Information [Line Items]
Revenues	118,499	115,952	347,317	344,149
Expenses	115,806	105,523	336,709	312,126
Operating profit (loss)	2,693	10,429	10,608	32,023
Gain on sale of subsidiary	0	0	0	2,791
Segment profit (loss)	2,693	10,429	10,608	34,814
Investment Advisors [Member]
Segment Reporting Information [Line Items]
Revenues	94,318	85,258	275,302	243,820
Expenses	50,585	45,080	147,504	134,575
Operating profit (loss)	43,733	40,178	127,798	109,245
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	43,733	40,178	127,798	109,245
Institutional Investors [Member]
Segment Reporting Information [Line Items]
Revenues	80,411	76,222	235,483	223,793
Expenses	40,003	36,943	117,499	108,875
Operating profit (loss)	40,408	39,279	117,984	114,918
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	40,408	39,279	117,984	114,918
Investment Managers [Member]
Segment Reporting Information [Line Items]
Revenues	91,020	75,672	255,123	216,528
Expenses	59,831	48,588	165,743	140,831
Operating profit (loss)	31,189	27,084	89,380	75,697
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	31,189	27,084	89,380	75,697
Investments In New Businesses [Member]
Segment Reporting Information [Line Items]
Revenues	1,770	1,537	5,108	4,445
Expenses	5,063	5,348	15,067	15,935
Operating profit (loss)	(3,293)	(3,811)	(9,959)	(11,490)
Gain on sale of subsidiary	0	0	0	0
Segment profit (loss)	$ (3,293)	$ (3,811)	$ (9,959)	$ (11,490)

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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

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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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