Revenue Recognition - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenue Recognition [Line Items]
Length of academic year			210 days
Revenue recognized estimated reserve based on historical evidence	$ 2.3		$ 2.3		$ 2.3
ASC Topic 606 [Member]
Revenue Recognition [Line Items]
Revenue recognized for payments received from withdrawn students	$ 0.3	$ 0.2	$ 1.2	$ 0.8
Minimum [Member]
Revenue Recognition [Line Items]
Length of academic terms			56 days
Length of Non-Degree Professional Programs			112 days
Maximum [Member]
Revenue Recognition [Line Items]
Length of academic terms			84 days
Length of Non-Degree Professional Programs			364 days