Business Segment Information (Schedule Of Additional Information Pertaining To 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]
Capital Expenditures	$ 23,473	$ 14,560	$ 43,539	$ 28,646
Depreciation	6,599	6,434	13,399	12,881
Amortization	12,565	11,284	24,587	22,296
Private Banks [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	9,479	8,454	22,329	17,166
Depreciation	4,172	3,199	8,582	6,380
Amortization	8,876	7,769	17,339	15,480
Investment Advisors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	3,698	3,267	8,230	6,119
Depreciation	802	964	1,535	1,940
Amortization	2,897	2,585	5,747	5,138
Institutional Investors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	1,086	696	1,897	1,492
Depreciation	244	339	471	673
Amortization	426	425	749	824
Investment Managers [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	8,665	1,743	10,280	3,065
Depreciation	1,028	1,172	1,944	2,362
Amortization	275	275	491	541
Investments In New Businesses [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	153	121	259	215
Depreciation	171	547	539	1,095
Amortization	41	40	160	66
Total From Business Segments [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	23,081	14,281	42,995	28,057
Depreciation	6,417	6,221	13,071	12,450
Amortization	12,515	11,094	24,486	22,049
Corporate Overhead [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	392	279	544	589
Depreciation	182	213	328	431
Amortization	$ 50	$ 190	$ 101	$ 247

The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Future cash outflow to pay for purchases of fixed assets that have occurred.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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