Investments - Summary of Investments (Details) - USD ($) $ in Thousands		Jun. 30, 2025	Dec. 31, 2024
Investments [Abstract]
Amortized cost		$ 1,330,007	$ 1,402,258
Gross unrealized gains		478	1,607
Gross unrealized losses		(876)	(399)
Estimated fair value		1,329,609	1,403,466
Amortized cost		716,807	654,600
Gross unrealized gains		2,029	984
Gross unrealized losses		(490)	(3,042)
Estimated fair value		718,346	652,542
Amortized cost		2,046,814	2,056,858
Gross unrealized gains		2,507	2,591
Gross unrealized losses		(1,366)	(3,441)
Estimated fair value		2,047,955	2,056,008
Amortized cost		16,802	35,012
Gross unrealized gains		25,039	25,027
Gross unrealized losses		(16,036)	(13,753)
Estimated fair value		25,805	46,286
Amortized cost		2,063,616	2,091,870
Gross unrealized gains		27,546	27,618
Gross unrealized losses		(17,402)	(17,194)
Estimated fair value		2,073,760	2,102,294
Corporate Debt Securities [Member]
Investments [Abstract]
Amortized cost	[1]	607,088	593,810
Gross unrealized gains		242	487
Gross unrealized losses		(373)	(240)
Estimated fair value		606,957	594,057
Amortized cost		458,306	439,561
Gross unrealized gains		1,484	723
Gross unrealized losses		(361)	(2,275)
Estimated fair value		459,429	438,009
Debt Securities Issued by U.S. Government Agencies [Member]
Investments [Abstract]
Amortized cost		122,690	143,647
Gross unrealized gains		66	287
Gross unrealized losses		(53)	(39)
Estimated fair value		122,703	143,895
Amortized cost		71,028	65,255
Gross unrealized gains		178	137
Gross unrealized losses		(87)	(289)
Estimated fair value		71,119	65,103
Debt Securities Issued by the U.S. Treasury [Member]
Investments [Abstract]
Amortized cost	[1]	593,378	657,285
Gross unrealized gains		168	825
Gross unrealized losses		(449)	(120)
Estimated fair value		593,097	657,990
Amortized cost		184,559	149,086
Gross unrealized gains		366	124
Gross unrealized losses		(41)	(476)
Estimated fair value		184,884	148,734
Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]
Investments [Abstract]
Amortized cost		6,851	7,516
Gross unrealized gains		2	8
Gross unrealized losses		(1)	0
Estimated fair value		6,852	7,524
Amortized cost		2,216
Gross unrealized gains		1
Gross unrealized losses		0
Estimated fair value		2,217
Other Municipal Debt Securities [Member]
Investments [Abstract]
Amortized cost		698	698
Gross unrealized gains		0	0
Gross unrealized losses		(1)	(2)
Estimated fair value		697	696
Publicly Traded Equity Securities [Member]
Investments [Abstract]
Amortized cost	[2]	11,897	11,897
Gross unrealized gains		38	26
Gross unrealized losses		(8,946)	(6,660)
Estimated fair value		2,989	5,263
Privately Held Equity Securities [Member]
Investments [Abstract]
Amortized cost	[3]	4,905	23,115
Gross unrealized gains		25,001	25,001
Gross unrealized losses		(7,090)	(7,093)
Estimated fair value		$ 22,816	$ 41,023

[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, 2025, we recorded a $2.3 million net unrealized loss 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, 2025, the amortized cost of our privately held equity securities decreased because we recorded a loss of $18.2 million in our condensed consolidated statements of operations related to an impairment of our investment in a privately held company.