Share-Based Compensation (Details 1) (USD $) In Thousands	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Share-based Compensation Expense
Share-based Compensation Expense	$ 3,130	$ 2,338
Tax effect of share-based compensation
Tax effect of share-based compensation	(1,252)	(935)
Share-based compensation expense, net of tax	1,878	1,403
Instructional Costs and Services [Member]
Share-based Compensation Expense
Share-based Compensation Expense	1,409	918
Selling and Promotional Expense [Member]
Share-based Compensation Expense
Share-based Compensation Expense	149	100
General and Administrative Expense [Member]
Share-based Compensation Expense
Share-based Compensation Expense	$ 1,572	$ 1,320

Represents the expense recognized during the period arising from share-based compensation arrangements (for example, shares of stock, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64
-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph g(1)

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14
-Section F

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration