Investment Information - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) lots	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) lots	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) lots
Continuous unrealized loss, qualitative disclosures:
Number of positions in an unrealized loss position (lots) | lots	9,590		9,590		4,700
Total number of positions (lots) | lots	11,500		11,500		10,240
Largest single loss	$ 7,200		$ 7,200		$ 1,100
Narrative items:
Equity securities, at fair value	809,869		809,869		$ 1,804,170
Equity in net (loss) income of investment funds accounted for using the equity method	$ (18,861)	$ 105,398	$ 75,505	$ 299,270
Time lag for reporting			3 months
Minimum
Narrative items:
Time lag for reporting			1 month
Maximum
Narrative items:
Time lag for reporting			3 months