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Compensation and Benefits - Change in Value of Investments (Details) - Long-Term Cash Awards - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Compensation and benefits
Schedule of Investments [Line Items]
Compensation and benefits	$ 83	$ 0	$ 297	$ 0
Other net investment gain (loss)
Schedule of Investments [Line Items]
Net investment gain (loss)	$ (356)	$ 0	$ 2,117	$ 0

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Long-term Incentive Compensation Expense, Impact of Change in Value of Investments

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Amount of realized and unrealized gain (loss) on investment.

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