Intangible Assets, net - Schedule of Intangible Assets (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Mar. 06, 2024	Jan. 09, 2024
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 279,838,000		$ 279,838,000		$ 303,668,000
Impairment	(700,000)		(695,000)		(52,918,000)
Accumulated Amortization	(19,810,000)		(19,810,000)		(14,061,000)
Net Carrying Amount	259,333,000		259,333,000		189,777,000
Foreign currency translation differences			(1,000,000.0)		7,400,000
Non-amortized intangible assets
Impairment			0		0
Intangible Assets, Gross Carrying Amount	525,738,000		525,738,000		549,568,000
Intangible Assets, Impairment	(695,000)	$ (29,393,000)	(695,000)	$ (29,393,000)	(52,918,000)
Intangible Assets, Net Carrying Amount	505,233,000		505,233,000		435,677,000
Pointwise Partners Limited ("PW") And East End Advisors, LLC ("EEA")
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			77,100,000
Alvarium RE Limited ("ARE") | Strategic Alternatives | Entity owned by management Of Alvarium Home REIT Advisors Ltd (“AHRA”)
Finite-Lived Intangible Assets [Line Items]
Impairment					(29,400,000)
Disposal | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					(254,000)
Held for Sale
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					(46,658,000)
Held for Sale | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					(46,658,000)
Disposal group, disposed of by sale, not discontinued operations | LXi Reit Advisors Limited (“LRA”) | LondonMetric Property Plc | Strategic Alternatives | Fund management
Finite-Lived Intangible Assets [Line Items]
Impairment					(23,500,000)
Ownership percentage in disposed asset (in percent)							100.00%
Consideration receivable						$ 33,100,000	$ 33,100,000
Contingent consideration receivable						$ 5,100,000	$ 5,100,000
Gain (loss) on disposal			0
Investment management agreements
Non-amortized intangible assets
Investment management agreements	$ 245,900,000		$ 245,900,000		$ 245,900,000
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	22 years 9 months 18 days		22 years 9 months 18 days		25 years 3 months 18 days
Gross Carrying Amount	$ 258,765,000		$ 258,765,000		$ 186,832,000
Impairment			0		0
Accumulated Amortization	(12,139,000)		(12,139,000)		(7,180,000)
Net Carrying Amount	$ 246,626,000		$ 246,626,000		177,270,000
Customer relationships | Disposal | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					(254,000)
Customer relationships | Held for Sale | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					$ (2,128,000)
Investment management agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	20 years 7 months 6 days		20 years 7 months 6 days		19 years 7 months 6 days
Gross Carrying Amount	$ 6,673,000		$ 6,673,000		$ 100,269,000
Impairment			(695,000)		(50,283,000)
Accumulated Amortization	(4,619,000)		(4,619,000)		(4,545,000)
Net Carrying Amount	$ 1,359,000		$ 1,359,000		2,142,000
Investment management agreements | Disposal | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					0
Investment management agreements | Held for Sale | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					$ (43,299,000)
Trade names
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	9 years 4 months 24 days		9 years 4 months 24 days		10 years
Gross Carrying Amount	$ 12,478,000		$ 12,478,000		$ 14,945,000
Impairment			0		(2,635,000)
Accumulated Amortization	(2,115,000)		(2,115,000)		(1,514,000)
Net Carrying Amount	$ 10,363,000		$ 10,363,000		9,565,000
Trade names | Disposal | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					0
Trade names | Held for Sale | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					$ (1,231,000)
Acquired internally developed software
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	5 years		5 years		5 years
Gross Carrying Amount	$ 1,300,000		$ 1,300,000		$ 1,000,000
Impairment			0		0
Accumulated Amortization	(315,000)		(315,000)		(200,000)
Net Carrying Amount	$ 985,000		$ 985,000		800,000
Acquired internally developed software | Disposal | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					0
Acquired internally developed software | Held for Sale | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					$ 0
Other intangible asset
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	0 years		0 years		0 years
Gross Carrying Amount	$ 622,000		$ 622,000		$ 622,000
Impairment			0		0
Accumulated Amortization	(622,000)		(622,000)		(622,000)
Net Carrying Amount	$ 0		$ 0		0
Other intangible asset | Disposal | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					0
Other intangible asset | Held for Sale | Family Office Service ("FOS")
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization					$ 0