Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Capital Expenditures	$ 86,568	$ 81,789	$ 73,881
Depreciation	27,311	26,440	24,044
Amortization	48,275	45,392	42,630
Assets	1,853,369	1,636,823
Private Banks [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	47,526	45,940	41,972
Depreciation	16,479	13,222	12,348
Amortization	32,696	31,675	29,819
Assets	523,214	471,435
Investment Advisors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	17,450	17,610	13,206
Depreciation	3,364	3,880	3,410
Amortization	10,930	10,458	9,880
Assets	139,697	160,717
Institutional Investors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	4,020	4,319	5,301
Depreciation	1,121	1,367	1,200
Amortization	1,599	1,674	1,558
Assets	117,286	109,879
Investment Managers [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	15,863	11,209	10,119
Depreciation	4,698	4,877	4,040
Amortization	2,593	1,092	1,029
Assets	278,540	158,621
Investments In New Businesses [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	546	726	736
Depreciation	826	2,197	2,278
Amortization	239	146	116
Assets	19,269	4,910
Total From Business Segments [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	85,405	79,804	71,334
Depreciation	26,488	25,543	23,276
Amortization	48,057	45,045	42,402
Assets	1,078,006	905,562
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	1,163	1,985	2,547
Depreciation	823	897	768
Amortization	218	347	$ 228
Assets	$ 775,363	$ 731,261

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
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-Section 45
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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Future cash outflow to pay for purchases of fixed assets that have occurred.

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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.

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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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No definition available.

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