Revenue Recognition - Graduation Fund (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Graduation Fund [Roll Forward]
Balance at beginning of period	$ 53,314	$ 49,641
Revenue deferred	21,067	26,462
Benefit redeemed	(22,357)	(22,789)
Balance at end of period	52,024	53,314
Undergraduate Degree Programs
Graduation Fund [Roll Forward]
Balance at beginning of period	52,600
Balance at end of period	$ 48,600	$ 52,600