Restricted Cash and Investments - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Restricted Investments Note [Abstract]
Cash and cash equivalents	$ 484,237	$ 595,381	$ 572,828
Restricted cash included in restricted cash and short-term investments	7,100		67,600
Total cash, cash equivalents and restricted cash reported in the consolidated statements of cash flows	$ 491,337	$ 625,781	$ 640,428	$ 581,150