Investments, Summary of Investments (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2023 USD ($) Company	Dec. 31, 2022 USD ($)
Ownership Interests in Private and Public Companies [Abstract]
Number of privately held companies in which there is an equity ownership interest of less than 20% | Company		7
Number of publicly held 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		$ 1,316,219	$ 1,223,522
Gross unrealized gains		415	64
Gross unrealized losses		(5,238)	(12,018)
Estimated fair value		1,311,396	1,211,568
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		651,628	525,314
Gross unrealized gains		3,063	130
Gross unrealized losses		(1,197)	(15,621)
Estimated fair value		653,494	509,823
Available-for-sale Debt Securities [Abstract]
Amortized cost		1,967,847	1,748,836
Gross unrealized gains		3,478	194
Gross unrealized losses		(6,435)	(27,639)
Estimated fair value		1,964,890	1,721,391
Equity Securities [Abstract]
Amortized cost		35,012	35,012
Gross unrealized gains		25,237	17,257
Gross unrealized losses		(10,957)	(1,358)
Estimated fair value		49,292	50,911
Available-for-sale Debt and Equity Securities [Abstract]
Amortized cost		2,002,859	1,783,848
Gross unrealized gains		28,715	17,451
Gross unrealized losses		(17,392)	(28,997)
Estimated fair value		2,014,182	1,772,302
Corporate Debt Securities [Member]
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost	[1]	559,967	513,790
Gross unrealized gains		157	23
Gross unrealized losses		(2,625)	(4,365)
Estimated fair value		557,499	509,448
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		243,151	227,631
Gross unrealized gains		1,270	14
Gross unrealized losses		(692)	(10,143)
Estimated fair value		243,729	217,502
Debt Securities Issued by U.S. Government Agencies [Member]
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost		224,711	133,585
Gross unrealized gains		64	0
Gross unrealized losses		(611)	(1,829)
Estimated fair value		224,164	131,756
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		110,138	34,339
Gross unrealized gains		547	0
Gross unrealized losses		(21)	(1,040)
Estimated fair value		110,664	33,299
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]	513,784	512,655
Gross unrealized gains		152	23
Gross unrealized losses		(1,889)	(5,124)
Estimated fair value		512,047	507,554
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		294,873	245,030
Gross unrealized gains		1,239	0
Gross unrealized losses		(480)	(4,109)
Estimated fair value		295,632	240,921
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		17,757	57,484
Gross unrealized gains		42	18
Gross unrealized losses		(113)	(686)
Estimated fair value		17,686	56,816
Available-for-sale Debt Securities with Maturity of More Than One Year [Abstract]
Amortized cost		3,466	18,314
Gross unrealized gains		7	116
Gross unrealized losses		(4)	(329)
Estimated fair value		3,469	18,101
Other Municipal Debt Securities [Member]
Available-for-sale Debt Securities with Maturity of One Year or Less [Abstract]
Amortized cost			6,008
Gross unrealized gains			0
Gross unrealized losses			(14)
Estimated fair value			5,994
Publicly Traded Equity Securities [Member]
Equity Securities [Abstract]
Amortized cost	[2]	11,897	11,897
Gross unrealized gains		236	0
Gross unrealized losses		(5,832)	(1,358)
Estimated fair value		6,301	10,539
Available-for-sale Debt and Equity Securities [Abstract]
Unrealized loss on equity securities		(4,200)
Privately Held Equity Securities [Member]
Equity Securities [Abstract]
Amortized cost	[3]	23,115	23,115
Gross unrealized gains		25,001	17,257
Gross unrealized losses		(5,125)	0
Estimated fair value		42,991	$ 40,372
Available-for-sale Debt and Equity Securities [Abstract]
Unrealized gain on equity securities		$ 2,600

[1] Includes investments classified as cash equivalents in our 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 year ended December 31, 2023, we recorded a $4.2 million net unrealized loss in our 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 year ended December 31, 2023, we recorded a $2.6 million net unrealized gain in our consolidated statements of operations related to changes in the fair value of our investments in privately held companies.