Summary of Significant Accounting Policies - Schedule of Restatements on Consolidated Income Statement (Detail) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Costs and expenses:
Technology and academic services	$ 11,101				$ 10,494			$ 32,476	$ 31,095
Counseling services and support	51,116				46,100			152,701	138,382
Marketing and communication	31,546				28,130			90,168	82,865
General and administrative	10,092				8,343			23,273	21,182
University related expenses	6,569				83,450			173,735	237,784
Total costs and expenses	$ 126,034				176,517			$ 489,953	$ 511,308
As Reported [Member]
Costs and expenses:
General and administrative		$ 11,969	$ 11,309	$ 10,845	12,915	$ 10,058	$ 9,941
Instructional costs and services		102,237	111,027	108,933	104,303	95,030	102,574
Admissions advisory and related		34,254	34,854	34,061	31,426	31,085	31,972
Advertising		27,602	25,715	23,678	25,523	24,776	24,631
Marketing and promotional		2,268	2,684	2,555	2,350	2,264	2,460
Total costs and expenses		178,330	185,589	180,072	176,517	163,213	171,578
As Reclassified [Member]
Costs and expenses:
Technology and academic services		10,678	10,697	10,739	10,494	10,220	10,381
Counseling services and support		50,838	50,747	50,213	46,100	45,970	46,312
Marketing and communication		30,095	28,527	26,227	28,130	27,426	27,309
General and administrative		5,762	7,419	5,975	8,343	5,806	7,033
University related expenses		79,517	87,649	86,356	83,450	73,791	80,543
Loss on transaction		1,440	550	562
Total costs and expenses		$ 178,330	$ 185,589	$ 180,072	$ 176,517	$ 163,213	$ 171,578