Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Capital expenditure	$ 15,229	$ 17,758	$ 34,850	$ 33,630
Depreciation	8,781	8,286	17,312	16,384
Amortization	9,630	16,508	19,054	33,395
Operating Segments
Segment Reporting Information [Line Items]
Capital expenditure	14,867	17,313	33,873	32,740
Depreciation	8,575	8,107	16,902	16,022
Amortization	9,565	16,438	18,925	33,254
Operating Segments \| Private Banks
Segment Reporting Information [Line Items]
Capital expenditure	8,001	8,541	17,072	15,763
Depreciation	5,450	5,554	10,804	10,660
Amortization	4,718	8,261	9,364	16,800
Operating Segments \| Investment Advisors
Segment Reporting Information [Line Items]
Capital expenditure	3,615	3,423	7,954	6,450
Depreciation	549	469	1,017	925
Amortization	1,945	3,158	3,763	6,391
Operating Segments \| Institutional Investors
Segment Reporting Information [Line Items]
Capital expenditure	457	1,028	1,105	1,977
Depreciation	303	285	585	574
Amortization	1,829	2,257	3,653	4,540
Operating Segments \| Investment Managers
Segment Reporting Information [Line Items]
Capital expenditure	2,592	4,113	7,198	8,137
Depreciation	2,210	1,755	4,365	3,775
Amortization	929	2,577	1,856	5,153
Operating Segments \| Investments In New Businesses
Segment Reporting Information [Line Items]
Capital expenditure	202	208	544	413
Depreciation	63	44	131	88
Amortization	144	185	289	370
Corporate overhead
Segment Reporting Information [Line Items]
Capital expenditure	362	445	977	890
Depreciation	206	179	410	362
Amortization	$ 65	$ 70	$ 129	$ 141

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

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