Segment Reporting - Summary Financial Information by Reporting Segment (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Significant legal settlements charge	$ 5.0	$ 6.0	$ 3.5	$ 6.5
All Other Campuses [Member]
Segment Reporting Information [Line Items]
Significant legal settlements charge					$ 14.6	$ 6.5
Charge related to remaining lease obligations					$ 9.4	$ 14.8	$ 31.0
University Group [Member] \| AIU [Member]
Segment Reporting Information [Line Items]
Significant legal settlements charge							$ 32.0