Restricted Cash and Investments - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Restricted Investments Note [Abstract]
Cash and cash equivalents	$ 467,353	$ 579,350	$ 561,101
Restricted cash included in Restricted cash and investments	39,200		0
Total cash, cash equivalents and restricted cash reported in the consolidated statements of cash flows	$ 506,553	$ 581,150	$ 561,101	$ 405,511