Segment Operating Results - (Footnotes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Other Revenue, net	$ 19,196	$ (28,648)	$ 24,723
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		20,337
Special Charges, Including Business Realignment Costs	8,554	46,645	10,141
Acquisition and Transition Costs	7	562	1,013
Total Other Expenses	8,561	49,457	36,865
Investment Banking [Member]
Segment Reporting Information [Line Items]
Other Revenue, net	19,370	(20,770)	18,431
Interest expense on Notes Payable and Line of Credit	17,586	18,197	12,917
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		21,070
Amortization of LP Units and Certain Other Awards	0	1,067	18,183
Special Charges, Including Business Realignment Costs	0	46,600	7,202
Acquisition and Transition Costs	7	262	705
Intangible Asset and Other Amortization	0	1,183	7,528
Total Other Expenses	7	49,112	33,618
Investment Management [Member]
Segment Reporting Information [Line Items]
Other Revenue, net	(174)	(7,878)	6,292
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		6,295
Net Loss on Sale and Wind-down of Operations in Mexico in 2020 and Release of Cumulative Foreign Exchange Losses		3,441
Special Charges, Including Business Realignment Costs	8,554	45	2,939
Acquisition and Transition Costs	0	300	308
Total Other Expenses	$ 8,554	$ 345	$ 3,247