Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Capital Expenditures	$ 77,171	$ 73,316	$ 86,568
Depreciation	29,436	28,792	27,311
Amortization	51,419	48,895	48,275
Assets	2,151,370	1,971,668
Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	74,857	71,809	85,405
Depreciation	28,130	27,587	26,488
Amortization	51,189	48,664	48,057
Assets	1,242,085	1,162,058
Operating Segments \| Private Banks
Segment Reporting Information [Line Items]
Capital Expenditures	33,068	36,763	47,526
Depreciation	14,349	13,773	16,479
Amortization	29,054	27,312	32,696
Assets	567,796	558,451
Operating Segments \| Investment Advisors
Segment Reporting Information [Line Items]
Capital Expenditures	17,413	16,572	17,450
Depreciation	4,653	4,607	3,364
Amortization	10,311	9,668	10,930
Assets	165,556	143,042
Operating Segments \| Institutional Investors
Segment Reporting Information [Line Items]
Capital Expenditures	4,057	3,863	4,020
Depreciation	1,600	1,672	1,121
Amortization	1,726	1,707	1,599
Assets	115,012	109,081
Operating Segments \| Investment Managers
Segment Reporting Information [Line Items]
Capital Expenditures	18,970	13,639	15,863
Depreciation	7,145	6,988	4,698
Amortization	9,358	9,382	2,593
Assets	373,986	318,342
Operating Segments \| Investments In New Businesses
Segment Reporting Information [Line Items]
Capital Expenditures	1,349	972	546
Depreciation	383	547	826
Amortization	740	595	239
Assets	19,735	33,142
Corporate Overhead
Segment Reporting Information [Line Items]
Capital Expenditures	2,314	1,507	1,163
Depreciation	1,306	1,205	823
Amortization	230	231	$ 218
Assets	$ 909,285	$ 809,610

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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The expense recognized in the current period that allocates the cost of nonproduction tangible assets over their useful lives.

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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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