Other Assets - Schedule of Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses, net of current portion	$ 19,852	$ 22,418
Equity method investments	15,582	15,795	$ 15,795
Cloud computing arrangements	5,957	6,385
Other investments	3,576	2,527
Tuition receivable, non-current	2,466	3,585
Other	4,864	4,218
Other assets	$ 52,297	$ 54,928