Revenue Recognition - Graduation Fund (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Graduation Fund [Roll Forward]
Balance at beginning of period	$ 52,024	$ 53,314
Revenue deferred	12,647	15,005
Benefit redeemed	(16,295)	(16,733)
Balance at end of period	$ 48,376	$ 51,586