Significant Accounting Policies - Tuition Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Tuition receivable	$ 128,250	$ 110,066
Allowance for credit losses	(45,877)	(47,113)
Tuition receivable, net	82,373	62,953
Tuition receivable, noncurrent	2,541	2,673
Other Noncurrent Assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Tuition receivable, noncurrent	$ 2,500	$ 2,700