Investments - Summary of Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Investment in privately held entities that do not report NAV, downward price adjustment	$ (1,300)
Investments in privately held entities that do not report NAV, cumulative impairment loss	(41,800)
Unrealized gains	43,632	$ 374,033	$ 161,489
Investment commitments	$ 391,000
Limited Partnership Maximum Expiration Terms	11 years
Weighted-average remaining liquidation term (in years)	5 years 2 months 12 days
Limited Partnership Liquidation, Expected Initial Term (In Years)	10 years
Summary of Investment [Abstract]
Investment at fair value, cost	$ 1,007,303	835,438
Cumulative unrealized gains (losses) on investments	797,673	775,676
Investments accounted for under the equity method	71,588
Total investments held at adjusted carrying value or fair value	1,876,564
Total investments	1,876,564	1,611,114
Investments in publicly traded companies
Summary of Investment [Abstract]
Investment at fair value, cost	203,290	208,754
Cumulative unrealized gains (losses) on investments	280,527	351,076
Investment at fair value, book value	483,817	559,830
Investments in privately held entities that report NAV
Schedule of Investments [Line Items]
Investment commitments	$ 358,000
Weighted-average remaining liquidation term (in years)	9 years
Summary of Investment [Abstract]
Investment at fair value, cost	$ 385,692	334,341
Cumulative unrealized gains (losses) on investments	444,172	327,741
Investment at fair value, book value	829,864	662,082
Investments in privately held entities that do not report NAV | Entities with observable price change
Schedule of Investments [Line Items]
Investment in privately held entities that do not report NAV, cumulative price adjustment	31,200
Investment in privately held entities that do not report NAV, upward price adjustment	74,300
Annual adjustments recognized on investments in privately held entities that do not report NAV	(33,300)	3,100	(12,700)
Investments in privately held entities that do not report NAV, annual upward price adjustment	32,700	36,700	5,200
Investments in privately held entities that do not report NAV, annual downward price adjustment	(66,000)	(33,600)	(18,000)
Summary of Investment [Abstract]
Investment at fair value, cost	56,257	47,545
Cumulative unrealized gains (losses) on investments	72,974	96,859
Investment in privately held entities that do not report fair value, book value	129,231	144,404
Investments in privately held entities that do not report NAV | Entities without observable price changes
Summary of Investment [Abstract]
Investment at fair value, cost	362,064	244,798
Cumulative unrealized gains (losses) on investments	0	0
Investment in privately held entities that do not report fair value, book value	362,064	244,798
Total investments held
Schedule of Investments [Line Items]
Unrealized gains	$ 109,400	$ 392,700	$ 184,600