Share Repurchase Program (Details) (USD $)	12 Months Ended			36 Months Ended	5 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	21 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011	Mar. 31, 2014 April 2011Three-Year Share Repurchase Progam [Member]	Oct. 10, 2011 May 2011 One-Year Repurchase Plan [Member]	Aug. 31, 2012 May 2011 One-Year Repurchase Plan [Member]	Aug. 31, 2012 November 2011 18-Month Repurchase Plan [Member]	Aug. 31, 2013 November 2011 18-Month Repurchase Plan [Member]	Aug. 31, 2013 November 2011 18-Month Repurchase Plan [Member]	Aug. 31, 2013 November 2011 Repurchase Plan Increased Amount Authorized [Member]
Share Repurchase Program
Stock repurchase program, authorized amount				$ 100,000,000		$ 30,000,000			$ 30,000,000	$ 70,000,000
Number of treasury stock shares acquired	304,000	1,463,000	1,011,000		1,603,979		244,597	303,709	2,152,285
Treasury stock shares acquired, average cost per share					$ 18.70		$ 21.56	$ 26.84	$ 20.20
Stock repurchase program, remaining authorized amount								56,600,000
Total cost of repurchased common stock	$ 8,091,000	$ 26,752,000	$ 22,154,000					$ 8,100,000