Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Capital Expenditures	$ 52,536	$ 78,567	$ 77,171
Depreciation	33,481	30,959	29,436
Amortization	59,152	52,975	51,419
Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	51,385	75,727	74,857
Depreciation	32,463	29,918	28,130
Amortization	58,828	52,745	51,189
Operating Segments | Private Banks
Segment Reporting Information [Line Items]
Capital Expenditures	26,472	29,061	33,068
Depreciation	19,040	16,206	14,349
Amortization	34,159	30,240	29,054
Operating Segments | Investment Advisors
Segment Reporting Information [Line Items]
Capital Expenditures	11,100	15,588	17,413
Depreciation	3,646	4,821	4,653
Amortization	11,654	10,694	10,311
Operating Segments | Institutional Investors
Segment Reporting Information [Line Items]
Capital Expenditures	2,614	3,958	4,057
Depreciation	1,241	1,214	1,600
Amortization	2,321	1,707	1,726
Operating Segments | Investment Managers
Segment Reporting Information [Line Items]
Capital Expenditures	10,275	25,909	18,970
Depreciation	8,185	7,336	7,145
Amortization	9,955	9,365	9,358
Operating Segments | Investments In New Businesses
Segment Reporting Information [Line Items]
Capital Expenditures	924	1,211	1,349
Depreciation	351	341	383
Amortization	739	739	740
Corporate Overhead
Segment Reporting Information [Line Items]
Capital Expenditures	1,151	2,840	2,314
Depreciation	1,018	1,041	1,306
Amortization	$ 324	$ 230	$ 230