Equity Securities (Tables)

9 Months Ended

Sep. 30, 2021

Investments Debt And Equity Securities [Abstract]

Summary of Investments in Equity Securities, by Classification

Investments in equity securities, by classification, are summarized as follows:

(in thousands)	September 30, 2021		December 31, 2020
Marketable equity securities	$	760,758	$	464,126
Non-marketable equity securities		379,548		217,104
Equity method investments		69,373		68,781
	$	1,209,679	$	750,011

Summary of Investments in Marketable Equity Securities

Investments in marketable equity securities are summarized as follows:

(in thousands)	Cost		Estimated fair value
September 30, 2021
Preferred stocks	$	16,810	$	16,944
Common stocks (1)		443,137		743,814
	$	459,947	$	760,758
December 31, 2020
Preferred stocks	$	22,163	$	19,479
Common stocks		354,157		444,647
	$	376,320	$	464,126

Summary of Investments in Non-Marketable Equity Securities

Investments in non-marketable equity securities are summarized as follows:

(in thousands)	Cost			Unrealized gains	Carrying amount
September 30, 2021	$	198,155	$	181,393	$	379,548
December 31, 2020	$	200,858	$	16,246	$	217,104