Marketable Investment Securities - Schedule of Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Available-for-sale debt securities:
Total available-for-sale debt securities	$ 529,445	$ 880,815
Equity securities	147,870	142,943
Total marketable investment securities, including restricted amounts	677,315	1,023,758
Less: Restricted marketable investment securities	(10,411)	(13,262)
Marketable investment securities	666,904	1,010,496
Corporate bonds
Available-for-sale debt securities:
Total available-for-sale debt securities	227,482	289,784
Commercial paper
Available-for-sale debt securities:
Total available-for-sale debt securities	289,046	498,358
Other debt securities
Available-for-sale debt securities:
Total available-for-sale debt securities	$ 12,917	$ 92,673

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