Investments, Summary of Investments (Details) $ in Thousands		6 Months Ended
		Jun. 30, 2024 USD ($) Company	Dec. 31, 2023 USD ($)
Ownership Interests in Private and Public Companies [Abstract]
Number of private companies in which there is an equity ownership interest of less than 20% | Company		7
Number of public companies in which there is an equity ownership interest of less than 20% | Company		3
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost		$ 1,343,698	$ 1,316,219
Gross unrealized gains		67	415
Gross unrealized losses		(3,026)	(5,238)
Estimated fair value		1,340,739	1,311,396
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		462,896	651,628
Gross unrealized gains		275	3,063
Gross unrealized losses		(2,334)	(1,197)
Estimated fair value		460,837	653,494
Available-for-sale Debt Securities [Abstract]
Amortized cost		1,806,594	1,967,847
Gross unrealized gains		342	3,478
Gross unrealized losses		(5,360)	(6,435)
Estimated fair value		1,801,576	1,964,890
Equity Securities [Abstract]
Amortized cost		35,012	35,012
Gross unrealized gains		25,335	25,237
Gross unrealized losses		(12,470)	(10,957)
Estimated fair value		47,877	49,292
Available-for-sale Debt and Equity Securities [Abstract]
Amortized cost		1,841,606	2,002,859
Gross unrealized gains		25,677	28,715
Gross unrealized losses		(17,830)	(17,392)
Estimated fair value		1,849,453	2,014,182
Corporate Debt Securities [Member]
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost	[1]	552,837	559,967
Gross unrealized gains		36	157
Gross unrealized losses		(1,569)	(2,625)
Estimated fair value		551,304	557,499
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		218,639	243,151
Gross unrealized gains		191	1,270
Gross unrealized losses		(874)	(692)
Estimated fair value		217,956	243,729
Debt Securities Issued by U.S. Government Agencies [Member]
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost		121,781	224,711
Gross unrealized gains		5	64
Gross unrealized losses		(310)	(611)
Estimated fair value		121,476	224,164
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		115,349	110,138
Gross unrealized gains		72	547
Gross unrealized losses		(317)	(21)
Estimated fair value		115,104	110,664
Debt Securities Issued by the U.S. Treasury [Member]
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost	[1]	650,997	513,784
Gross unrealized gains		12	152
Gross unrealized losses		(1,105)	(1,889)
Estimated fair value		649,904	512,047
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		127,240	294,873
Gross unrealized gains		12	1,239
Gross unrealized losses		(1,135)	(480)
Estimated fair value		126,117	295,632
Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost		18,083	17,757
Gross unrealized gains		14	42
Gross unrealized losses		(42)	(113)
Estimated fair value		18,055	17,686
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		1,668	3,466
Gross unrealized gains		0	7
Gross unrealized losses		(8)	(4)
Estimated fair value		1,660	3,469
Publicly Traded Equity Securities [Member]
Equity Securities [Abstract]
Amortized cost	[2]	11,897	11,897
Gross unrealized gains		334	236
Gross unrealized losses		(5,377)	(5,832)
Estimated fair value		6,854	6,301
Available-for-sale Debt and Equity Securities [Abstract]
Unrealized gain on equity securities		600
Privately Held Equity Securities [Member]
Equity Securities [Abstract]
Amortized cost	[3]	23,115	23,115
Gross unrealized gains		25,001	25,001
Gross unrealized losses		(7,093)	(5,125)
Estimated fair value		41,023	$ 42,991
Available-for-sale Debt and Equity Securities [Abstract]
Unrealized loss on equity securities		$ (2,000)

[1] Includes investments classified as cash equivalents in our condensed consolidated balance sheets.

[2] Our publicly traded equity securities are included in other current assets. We recognize publicly traded equity securities at fair value. In the six months ended June 30, 2024, we recorded a $0.6 million net unrealized gain in our condensed consolidated statements of operations related to changes in the fair value of our investments in publicly traded companies.

[3] Our privately held equity securities are included in deposits and other assets. We recognize our privately held equity securities at cost minus impairments, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer, which are Level 3 inputs. In the six months ended June 30, 2024, we recorded a loss of $2.0 million in our condensed consolidated statements of operations related to changes in the fair value of our investments in privately held companies.