Share-Based Compensation Plans - Share-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 9,936	$ 7,811	$ 6,452
Tax effect of share-based compensation	(3,974)	(3,124)	(2,581)
Share-based compensation expense, net of tax	5,962	4,687	3,871
Instructional Costs and Services [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	5,246	3,809	2,935
Admissions Advisory and Related [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	134	224	157
Marketing and Promotional [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	229	169	140
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 4,327	$ 3,609	$ 3,220