Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Capital Expenditures	$ 17,739	$ 25,352	$ 55,023	$ 68,891
Depreciation	7,255	6,948	21,515	20,347
Amortization	12,405	13,745	36,420	38,332
Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	17,279	24,975	53,889	67,970
Depreciation	6,938	6,740	20,610	19,811
Amortization	12,347	13,695	36,247	38,181
Operating Segments \| Private Banks
Segment Reporting Information [Line Items]
Capital Expenditures	7,999	14,671	27,767	37,000
Depreciation	3,427	4,374	10,069	12,956
Amortization	6,943	9,125	20,317	26,464
Operating Segments \| Investment Advisors
Segment Reporting Information [Line Items]
Capital Expenditures	3,927	5,421	12,471	13,651
Depreciation	1,168	759	3,378	2,294
Amortization	2,445	2,973	7,203	8,720
Operating Segments \| Institutional Investors
Segment Reporting Information [Line Items]
Capital Expenditures	962	1,260	2,926	3,157
Depreciation	410	248	1,310	719
Amortization	427	425	1,281	1,174
Operating Segments \| Investment Managers
Segment Reporting Information [Line Items]
Capital Expenditures	4,104	3,450	9,994	13,730
Depreciation	1,796	1,197	5,411	3,141
Amortization	2,346	1,132	7,036	1,623
Operating Segments \| Investments In New Businesses
Segment Reporting Information [Line Items]
Capital Expenditures	287	173	731	432
Depreciation	137	162	442	701
Amortization	186	40	410	200
Corporate
Segment Reporting Information [Line Items]
Capital Expenditures	460	377	1,134	921
Depreciation	317	208	905	536
Amortization	$ 58	$ 50	$ 173	$ 151

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.

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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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