Current Expected Credit Losses - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Current expected credit losses reserve	$ 26,200,000	$ 14,900,000	$ 2,400,000	$ 2,600,000
Current-period provision for expected credit losses	11,300,000	12,500,000	(200,000)
Loans, forgivable loans and other receivables from employees and partners, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Current expected credit losses reserve	2,300,000	2,500,000	1,700,000	1,600,000
Current-period provision for expected credit losses	(200,000)	800,000	100,000
Accrued commissions and other receivables, net
Financing Receivable, Allowance for Credit Loss [Line Items]
Current expected credit losses reserve	5,000,000.0	5,400,000	700,000	$ 1,000,000.0
Current-period provision for expected credit losses	(400,000)	$ 4,700,000	$ (300,000)
Accrued commissions and other receivables, net | Russia/Ukraine Conflit
Financing Receivable, Allowance for Credit Loss [Line Items]
Current-period provision for expected credit losses	$ 4,500,000