Revenue Recognition - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) Portfolio	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) Portfolio	Jun. 30, 2017 USD ($)
Revenue Recognition [Line Items]
Length of academic year			210 days
Revenue recognized estimated reserve based on historical evidence	$ 1.0		$ 1.0
ASC Topic 606 [Member]
Revenue Recognition [Line Items]
Revenue recognized for payments received from withdrawn students	$ 0.3	$ 0.3	$ 0.7	$ 0.8
Number of portfolio for revenue recognition | Portfolio	1		1
Minimum [Member]
Revenue Recognition [Line Items]
Length of academic terms			70 days
Minimum [Member] | ASC Topic 606 [Member]
Revenue Recognition [Line Items]
Days required for documentation to be eligible and approved for funding			90 days
Maximum [Member]
Revenue Recognition [Line Items]
Length of academic terms			77 days
Maximum [Member] | ASC Topic 606 [Member]
Revenue Recognition [Line Items]
Days required for documentation to be eligible and approved for funding			120 days