Stock and Savings Plans (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2012
Share-based compensation expense [Line Items]
Share-based compensation	$ 42,819	$ 49,462	$ 78,705
Tax effect of share-based compensation	(16,754)	(18,986)	(29,874)
Share-based compensation expense, net of tax	26,065	30,476	48,831
Instructional and student advisory [Member]
Share-based compensation expense [Line Items]
Share-based compensation	10,727	20,060	27,731
Marketing [Member]
Share-based compensation expense [Line Items]
Share-based compensation	3,702	5,182	6,807
Admissions advisory [Member]
Share-based compensation expense [Line Items]
Share-based compensation	813	849	1,691
General and administrative [Member]
Share-based compensation expense [Line Items]
Share-based compensation	23,296	21,363	41,153
Restructuring and other charges [Member]
Share-based compensation expense [Line Items]
Share-based compensation	$ 4,281	$ 2,008	$ 1,323