Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Capital Expenditures	$ 17,162	$ 19,855	$ 27,740	$ 46,975
Depreciation	8,424	7,640	16,733	15,113
Amortization	14,723	13,140	29,075	26,217
Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	16,744	19,057	27,162	45,180
Depreciation	8,075	7,383	16,053	14,600
Amortization	14,598	13,082	28,892	26,102
Operating Segments \| Private Banks
Segment Reporting Information [Line Items]
Capital Expenditures	8,594	6,634	14,423	16,559
Depreciation	4,178	3,965	8,310	7,847
Amortization	8,633	7,464	17,209	14,885
Operating Segments \| Investment Advisors
Segment Reporting Information [Line Items]
Capital Expenditures	3,580	3,803	5,888	9,193
Depreciation	1,417	1,172	2,706	2,323
Amortization	2,909	2,664	5,536	5,316
Operating Segments \| Institutional Investors
Segment Reporting Information [Line Items]
Capital Expenditures	884	1,029	1,395	2,387
Depreciation	353	301	711	603
Amortization	427	427	853	854
Operating Segments \| Investment Managers
Segment Reporting Information [Line Items]
Capital Expenditures	3,373	7,259	5,004	16,291
Depreciation	2,027	1,869	4,080	3,681
Amortization	2,444	2,342	4,924	4,677
Operating Segments \| Investments In New Businesses
Segment Reporting Information [Line Items]
Capital Expenditures	313	332	452	750
Depreciation	100	76	246	146
Amortization	185	185	370	370
Corporate
Segment Reporting Information [Line Items]
Capital Expenditures	418	798	578	1,795
Depreciation	349	257	680	513
Amortization	$ 125	$ 58	$ 183	$ 115

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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