Fair Value Measurements - Fair Value Measurements (Details) - Recurring Basis [Member] - USD ($) $ in Thousands		Jun. 30, 2025		Dec. 31, 2024
Fair Value Measurements [Abstract]
Cash equivalents	[1]	$ 176,462		$ 180,445
Total		2,227,406		2,241,716
Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Cash equivalents	[1]	176,462		180,445
Total		957,432		992,432
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Cash equivalents	[1]	0		0
Total		1,269,974		1,249,284
Corporate Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		1,066,386	[2]	1,032,066	[3]
Corporate Debt Securities [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		0	[2]	0	[3]
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		1,066,386	[2]	1,032,066	[3]
Debt Securities Issued by U.S. Government Agencies [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	193,822		208,998
Debt Securities Issued by U.S. Government Agencies [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	0		0
Debt Securities Issued by U.S. Government Agencies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	193,822		208,998
Debt Securities Issued by the U.S. Treasury [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		777,981	[4]	806,724	[3]
Debt Securities Issued by the U.S. Treasury [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		777,981	[4]	806,724	[3]
Debt Securities Issued by the U.S. Treasury [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities		0	[4]	0	[3]
Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	9,069		7,524
Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	0		0
Debt Securities Issued by States of the U.S. and Political Subdivisions of the States [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	9,069		7,524
Other Municipal Debt Securities [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	697		696
Other Municipal Debt Securities [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	0		0
Other Municipal Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Available-for-sale securities	[3]	697		696
Other Current Assets [Member] | Publicly Traded Equity Securities [Member]
Fair Value Measurements [Abstract]
Equity securities	[5]	2,989		5,263
Other Current Assets [Member] | Publicly Traded Equity Securities [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value Measurements [Abstract]
Equity securities	[5]	2,989		5,263
Other Current Assets [Member] | Publicly Traded Equity Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Abstract]
Equity securities	[5]	$ 0		$ 0

[1] Included in cash and cash equivalents.

[2] $29.9 million was included in cash and cash equivalents, with the difference included in short-term investments.

[3] Included in short-term investments.

[4] $24.4 million was included in cash and cash equivalents, with the difference included in short-term investments.

[5] Included in other current assets.