Revenue Recognition - Graduation Fund (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Graduation Fund [Roll Forward]
Balance at beginning of period	$ 46,842	$ 52,024
Revenue deferred	9,875	8,774
Benefit redeemed	(11,391)	(10,656)
Balance at end of period	$ 45,326	$ 50,142