Revenue Recognition - Summary of Disaggregation of Revenue by Major Source (Detail) - USD ($) $ in Thousands		3 Months Ended														12 Months Ended
		Dec. 31, 2020	[1]	Sep. 30, 2020	[1]	Jun. 30, 2020	[1]	Mar. 31, 2020	[1]	Dec. 31, 2019	Sep. 30, 2019	[2]	Jun. 30, 2019	[3]	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Total revenue		$ 171,159		$ 169,126		$ 176,035		$ 170,994		$ 158,451	$ 154,959		$ 156,441		$ 157,853	$ 687,314		$ 627,704		$ 581,296
Tuition [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																651,801		595,682		557,191
Technology Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																30,809		27,256		19,150
Other Miscellaneous Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[4]															1,969		2,118		2,204
Tuition and Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																684,579		625,056		578,545
Other [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[5]															2,735		2,648		2,751
University Group [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																686,868		627,637		580,690
University Group [Member] | CTU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																405,507		392,263	[6]	375,770
University Group [Member] | AIU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																281,361	[7],[8]	235,374	[9]	204,920
University Group [Member] | Tuition [Member] | CTU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																381,371		370,318		359,929
University Group [Member] | Tuition [Member] | AIU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																270,430	[7]	225,364		196,712
University Group [Member] | Technology Fees [Member] | CTU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																20,687		17,844		11,560
University Group [Member] | Technology Fees [Member] | AIU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																10,122	[7]	9,412		7,590
University Group [Member] | Other Miscellaneous Fees [Member] | CTU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[4]															1,283		1,690		1,769
University Group [Member] | Other Miscellaneous Fees [Member] | AIU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[4]															686	[7]	428		416
University Group [Member] | Tuition and Fees [Member] | CTU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																403,341		389,852		373,258
University Group [Member] | Tuition and Fees [Member] | AIU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue																281,238	[7]	235,204		204,718
University Group [Member] | Other [Member] | CTU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[5]															2,166		2,411		2,512
University Group [Member] | Other [Member] | AIU [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[5]															123	[7]	170		202
Corporate and Other [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[10]															446		67	[11]	606	[12]
Corporate and Other [Member] | Tuition [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[10]																			550
Corporate and Other [Member] | Other Miscellaneous Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[4],[10]																			19
Corporate and Other [Member] | Tuition and Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[10]																			569
Corporate and Other [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[5],[10]															$ 446		$ 67		$ 37

[1] 2020 results include the Trident acquisition commencing on the March 2, 2020 date of acquisition.

[2] Third quarter of 2019 net income included a $7.1 million significant legal settlement for the Oregon arbitration matter.

[3] Second quarter of 2019 net income included a $30.0 million significant legal settlement for the FTC matter, of which $23.3 million was non-deductible for income tax purposes during the second quarter of 2019.

[4] Other miscellaneous fees include student activity fees and graduation fees.

[5] Other revenue primarily includes contract training revenue and bookstore sales.

[6] CTU: a $18.6 million charge related to the FTC settlement.

[7] AIU includes revenue related to the Trident acquisition commencing on the March 2, 2020 date of acquisition.

[8] AIU results of operations and total assets include the Trident acquisition commencing on the March 2, 2020 date of acquisition and as of December 31, 2020.

[9] AIU: a $11.4 million charge related to the FTC settlement.

[10] Revenue recorded within Corporate and Other relates to certain bookstore sales and closed campuses which are now reported within this category as well as revenue not related to campus operations.

[11] Corporate and Other: a $7.1 million charge related to the Oregon arbitration matter for closed campuses.

[12] Corporate and Other: $14.6 million of charges related to significant legal settlements for the Surrett and multi-state AG matters and $9.4 million of charges related to remaining lease obligations for vacated space.