Restricted Cash and Cash Equivalents - Reconciliation of Cash, Cash Equivalents and Restricted Cash and Cash Equivalents (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 48,716,000	$ 95,073,000	$ 587,861,000
Restricted cash and cash equivalents - current	0		21,134,000
Restricted cash and investments - non-current	136,497,000	111,691,000	81,392,000
Less Restricted investments - non-current	(66,424,000)		(53,593,000)
Total cash, cash equivalents and restricted cash and cash equivalents shown in the statement of cash flows	$ 118,789,000	$ 143,843,000	$ 636,794,000	$ 548,322,000