Share-Based Compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Nov. 30, 2012	Nov. 30, 2011
Share-based compensation expense [Line Items]
Share-based compensation expense	$ 16,889	$ 20,892
Weighted average exercise price of options granted	$ 19.62
Stock options granted	26
Weighted average grant date fair value of options	$ 7.77
Instructional and student advisory [Member]
Share-based compensation expense [Line Items]
Share-based compensation expense	7,588	7,422
Marketing [Member]
Share-based compensation expense [Line Items]
Share-based compensation expense	2,043	2,234
Admissions advisory [Member]
Share-based compensation expense [Line Items]
Share-based compensation expense	170	447
General and administrative [Member]
Share-based compensation expense [Line Items]
Share-based compensation expense	6,023	10,789
Restructuring and other charges [Member]
Share-based compensation expense [Line Items]
Share-based compensation expense	$ 1,065	$ 0