Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Capital Expenditures	$ 18,786	$ 23,473	$ 37,284	$ 43,539
Depreciation	7,138	6,599	14,260	13,399
Amortization	12,161	12,565	24,015	24,587
Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	18,420	23,081	36,610	42,995
Depreciation	6,841	6,417	13,672	13,071
Amortization	12,104	12,515	23,900	24,486
Operating Segments \| Private Banks
Segment Reporting Information [Line Items]
Capital Expenditures	9,529	9,479	19,768	22,329
Depreciation	3,323	4,172	6,642	8,582
Amortization	6,747	8,876	13,374	17,339
Operating Segments \| Investment Advisors
Segment Reporting Information [Line Items]
Capital Expenditures	4,284	3,698	8,544	8,230
Depreciation	1,105	802	2,210	1,535
Amortization	2,401	2,897	4,758	5,747
Operating Segments \| Institutional Investors
Segment Reporting Information [Line Items]
Capital Expenditures	997	1,086	1,964	1,897
Depreciation	452	244	900	471
Amortization	427	426	854	749
Operating Segments \| Investment Managers
Segment Reporting Information [Line Items]
Capital Expenditures	3,370	8,665	5,890	10,280
Depreciation	1,806	1,028	3,615	1,944
Amortization	2,345	275	4,690	491
Operating Segments \| Investments In New Businesses
Segment Reporting Information [Line Items]
Capital Expenditures	240	153	444	259
Depreciation	155	171	305	539
Amortization	184	41	224	160
Corporate
Segment Reporting Information [Line Items]
Capital Expenditures	366	392	674	544
Depreciation	297	182	588	328
Amortization	$ 57	$ 50	$ 115	$ 101

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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