Financial Instruments (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($) position	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	$ 888,277	$ 881,708
Gross Unrealized Gain		14
Gross Unrealized Loss	(1,180)	(2,745)
Estimated Fair Value	887,097	878,977
Cash, cash equivalents and restricted cash	796,798	642,095	$ 381,113	$ 466,091
Short-term investments	90,299	236,882
Securities Sold	$ 0
Number of investments, unrealized loss position | position	15
Credit loss reserve	$ 0
Less than 12 Months, Fair value	23,923
12 Months or Longer, Fair value	66,376
Fair value	90,299
12 Months or Longer, Unrealized loss	(1,180)
Unrealized loss	(1,180)
Amortized Cost
Less than or equal to one year	75,440
Greater than one year but less than five years	16,039
Total	91,479
Fair Value
Less than or equal to one year	75,003
Greater than one year but less than five years	15,296
Total	90,299
Cash, cash equivalents, and restricted cash
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	796,798	642,095
Estimated Fair Value	796,798	642,095
U.S. Treasury securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	58,923	201,522
Gross Unrealized Gain		14
Gross Unrealized Loss	(109)	(1,118)
Estimated Fair Value	58,814	200,418
Less than 12 Months, Fair value	23,923
12 Months or Longer, Fair value	34,891
Fair value	58,814
12 Months or Longer, Unrealized loss	(109)
Unrealized loss	(109)
Municipal securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	32,556	38,091
Gross Unrealized Loss	(1,071)	(1,627)
Estimated Fair Value	31,485	$ 36,464
12 Months or Longer, Fair value	31,485
Fair value	31,485
12 Months or Longer, Unrealized loss	(1,071)
Unrealized loss	$ (1,071)