Note 13. Employee Stock Option and Retirement Plans (Detail) - Change in the Actual Financial Performance Level (USD $) In Thousands, unless otherwise specified		3 Months Ended
	Nov. 30, 2012	Nov. 30, 2011 November 2011 Annual Employee Performance-based Option Grant Review [Member] Financial Performance Level One [Member]		Nov. 30, 2011 November 2011 Annual Employee Performance-based Option Grant Review [Member] Financial Performance Level Two [Member]		Nov. 30, 2011 November 2011 Annual Employee Performance-based Option Grant Review [Member] Financial Performance Level Three [Member]		Nov. 30, 2011 November 2011 Annual Employee Performance-based Option Grant Review [Member] Financial Performance Level Four [Member]		Nov. 30, 2012 November 2012 Annual Employee Performance-Based Option Grant Review [Member] Financial Performance Level One [Member]		Nov. 30, 2012 November 2012 Annual Employee Performance-Based Option Grant Review [Member] Financial Performance Level Two [Member]		Nov. 30, 2012 November 2012 Annual Employee Performance-Based Option Grant Review [Member] Financial Performance Level Three [Member]		Nov. 30, 2012 November 2012 Annual Employee Performance-Based Option Grant Review [Member] Financial Performance Level Four [Member]
Vesting percentage		0.00%		20.00%		60.00%		100.00%		0.00%		20.00%		60.00%		100.00%
Total unamortized stock-based compensation expense	$ 53,700	$ 0		$ 2,452		$ 7,356		$ 12,260		$ 0		$ 4,628		$ 13,884		$ 23,140
One-time adjustment		0	[1]	1,188	[1]	3,564	[1]	5,940	[1]	(119)	[1]	0	[1]	238	[1]	476	[1]
Average remaining quarterly expense to be recognized		$ 0		$ 157		$ 471		$ 785		$ 0		$ 235		$ 705		$ 1,175

[1] Amounts represent the cumulative catch-up adjustment to be recorded if there was a change in the vesting percentage as of November 30, 2012.