Investments (Tables)

12 Months Ended

Dec. 31, 2021

Investments [Abstract]

Summary of investments

The following tables summarize our investments as of December 31, 2021 and 2020 (in thousands):

	December 31, 2021
	Cost		Unrealized Gains (Losses)		Carrying Amount
Publicly traded companies	$	203,290	$	280,527	$	483,817
Entities that report NAV	385,692		444,172		829,864
Entities that do not report NAV:
Entities with observable price changes	56,257		72,974		129,231
Entities without observable price changes	362,064		—		362,064
Investments accounted for under the equity method	N/A		N/A		71,588
Total investments	$	1,007,303	$	797,673	1,876,564

	December 31, 2020
	Cost		Unrealized Gains (Losses)		Carrying Amount
Publicly traded companies	$	208,754	$	351,076	$	559,830
Entities that report NAV	334,341		327,741		662,082
Entities that do not report NAV:
Entities with observable price changes	47,545		96,859		144,404
Entities without observable price changes	244,798		—		244,798
Total investments	$	835,438	$	775,676	$	1,611,114

Schedule of net investment income

Our investment income for the years ended December 31, 2021, 2020, and 2019 consisted of the following (in thousands):

	Year Ended December 31,
	2021		2020		2019
Realized gains	$	215,845	$	47,288	$	33,158
Unrealized gains	43,632		374,033		161,489
Investment income	$	259,477	$	421,321	$	194,647