Business Changes and Developments - Goodwill Associated with Acquisitions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Balance at beginning of period	$ 128,246	$ 129,126
Foreign Currency Translation and Other	(4,961)	(880)
Balance at end of period	123,285	128,246
Goodwill, Impaired, Accumulated Impairment Loss	38,528	38,528	$ 38,528
Goodwill, Gross	161,813	166,774	$ 167,654
Investment Banking and Equities [Member]
Goodwill [Roll Forward]
Balance at beginning of period	120,719	121,599
Foreign Currency Translation and Other	(4,961)	(880)
Balance at end of period	115,758	120,719
Investment Management [Member]
Goodwill [Roll Forward]
Balance at beginning of period	7,527	7,527
Foreign Currency Translation and Other	0	0
Balance at end of period	$ 7,527	$ 7,527