Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Net revenue	$ 193,393	$ 175,056	$ 562,246	$ 501,082
Costs and expenses:
Instructional costs and services	83,180	71,714	237,224	210,239
Admissions advisory and related, including $412 and $762 for the three months ended September 30, 2015 and 2014, respectively, and $1,406 and $2,373 for the nine months ended September 30, 2015 and 2014, respectively, to related parties	27,506	27,324	83,211	79,793
Advertising	19,360	16,491	57,810	48,954
Marketing and promotional	1,827	1,931	5,309	5,629
General and administrative	12,536	11,640	31,466	29,188
Total costs and expenses	144,409	129,100	415,020	373,803
Operating income	48,984	45,956	147,226	127,279
Interest expense	(313)	(576)	(834)	(1,455)
Interest and other income	201	43	585	377
Income before income taxes	48,872	45,423	146,977	126,201
Income tax expense	15,530	16,407	53,680	47,828
Net income	$ 33,342	$ 29,016	$ 93,297	$ 78,373
Earnings per share:
Basic income per share	$ 0.72	$ 0.64	$ 2.03	$ 1.72
Diluted income per share	$ 0.70	$ 0.62	$ 1.97	$ 1.67
Basic weighted average shares outstanding	46,063	45,651	45,956	45,486
Diluted weighted average shares outstanding	47,320	47,051	47,262	46,962