Organization and Basis of Presentation - Summary of Financial Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Equity securities:
Gross Unrealized Gain (Loss)	$ 16,681	$ (1,073)
Carrying Value	2,500		$ 2,500
Available for sale
Equity and Debt Securities, Amortized Cost	142,846		131,770
Equity and Debt Securities, Gross Unrealized Gain (Loss)	32,936		15,998
Equity and Debt Securities, Marketable Securities	175,782		147,768
Investment funds - debt securities
Equity securities:
Cost	61,673		49,646
Gross Unrealized Gain (Loss)	259		985
Carrying Value	61,932		50,631
Common stock and stock funds
Equity securities:
Cost	80,123		81,074
Gross Unrealized Gain (Loss)	32,408		15,001
Carrying Value	112,531		96,075
Investment-grade unsecured debt
Available for sale
Cost	1,050		1,050
Gross Unrealized Gain (Loss)	269		12
Carrying Value	$ 1,319		$ 1,062

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Amount of investment in marketable security.

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