Business Segment Information (Schedule Of Additional Information Pertaining To 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]
Capital Expenditures	$ 25,352	$ 31,206	$ 68,891	$ 59,852
Depreciation	6,948	6,576	20,347	19,457
Amortization	13,745	11,388	38,332	33,684
Private Banks [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	14,671	15,018	37,000	32,184
Depreciation	4,374	3,289	12,956	9,669
Amortization	9,125	7,972	26,464	23,452
Investment Advisors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	5,421	6,744	13,651	12,863
Depreciation	759	940	2,294	2,880
Amortization	2,973	2,626	8,720	7,764
Institutional Investors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	1,260	1,744	3,157	3,236
Depreciation	248	344	719	1,017
Amortization	425	425	1,174	1,249
Investment Managers [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	3,450	6,210	13,730	9,275
Depreciation	1,197	1,228	3,141	3,590
Amortization	1,132	275	1,623	816
Investments In New Businesses [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	173	379	432	594
Depreciation	162	549	701	1,644
Amortization	40	40	200	106
Total From Business Segments [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	24,975	30,095	67,970	58,152
Depreciation	6,740	6,350	19,811	18,800
Amortization	13,695	11,338	38,181	33,387
Corporate Overhead [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	377	1,111	921	1,700
Depreciation	208	226	536	657
Amortization	$ 50	$ 50	$ 151	$ 297

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
-Topic 350
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-Section 50
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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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-SubTopic 10
-Section 50
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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
-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

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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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