Equity Method Investments and Other - Carrying Value of Equity Method Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 102,111	$ 110,653
Equity method investments
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	69,229	74,628
Arena Special Opportunities Fund, LP units
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 38,137	$ 41,046
Equity method investments ownership percentage	15.90%	16.20%
JVM Funds LLC
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 17,831	$ 20,061
Equity method investments ownership percentage	10.10%	10.10%
Arena SOP LP units
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 2,530	$ 2,463
Equity method investments ownership percentage	12.60%	12.30%
RISCOM
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 4,689	$ 4,121
Equity method investments ownership percentage	20.00%	20.00%
Hudson Ventures Fund II LP units
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 4,634	$ 4,669
Equity method investments ownership percentage	2.50%	2.50%
Dowling Capital Partners LP units
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 652	$ 1,708
Equity method investments ownership percentage	5.00%	6.20%
Brewer Lane Ventures Fund II LP units
Schedule of Equity Method Investments [Line Items]
Recorded investment balance	$ 756	$ 560
Equity method investments ownership percentage	2.40%	2.50%