Revenue Recognition - Changes in Deferred Revenue Balances (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Deferred Revenue Arrangement [Line Items]
Gross deferred revenue, beginning balance		$ 45,801	$ 37,260	$ 51,694	$ 39,544
Revenue earned from balances existing		(40,345)	(32,921)	(44,068)	(36,606)
Billings during period	[1]	144,173	167,192	449,514	453,176
Revenue earned for new billings during the period		(113,946)	(111,961)	(423,230)	(397,130)
Other adjustments		(72)	(791)	1,701	(205)
Gross deferred revenue, ending balance		35,611	58,779	35,611	58,779
University Group [Member] | CTU [Member]
Deferred Revenue Arrangement [Line Items]
Gross deferred revenue, beginning balance		25,825	23,754	24,250	23,933
Revenue earned from balances existing		(23,375)	(21,533)	(22,289)	(22,192)
Billings during period	[1]	96,863	93,277	289,803	279,374
Revenue earned for new billings during the period		(72,054)	(70,837)	(265,587)	(256,923)
Other adjustments		(146)	(266)	936	203
Gross deferred revenue, ending balance		27,113	24,395	27,113	24,395
University Group [Member] | AIU [Member]
Deferred Revenue Arrangement [Line Items]
Gross deferred revenue, beginning balance		19,976	13,436	27,444	15,507
Revenue earned from balances existing		(16,970)	(11,341)	(21,779)	(14,310)
Billings during period	[1]	47,310	73,852	159,711	173,244
Revenue earned for new billings during the period		(41,892)	(41,106)	(157,643)	(139,736)
Other adjustments		74	(500)	765	(364)
Gross deferred revenue, ending balance		$ 8,498	34,341	$ 8,498	34,341
Corporate and Other [Member]
Deferred Revenue Arrangement [Line Items]
Gross deferred revenue, beginning balance	[2]		70		104
Revenue earned from balances existing	[2]		(47)		(104)
Billings during period	[1],[2]		63		558
Revenue earned for new billings during the period	[2]		(18)		(471)
Other adjustments	[2]		(25)		(44)
Gross deferred revenue, ending balance	[2]		$ 43		$ 43

[1] Billings during period includes adjustments for prior billings.

[2] Revenue recorded within Corporate and Other relates to closed campuses which are now reported within this category.