Note 13 - Employee Stock Option and Retirement Plans (Details) - Summary of Restricted Stock Award (USD $)	1 Months Ended	12 Months Ended
	Apr. 30, 2013	Aug. 31, 2013		Aug. 31, 2012		Aug. 31, 2011
Summary of Restricted Stock Award [Abstract]
Balance		383,000		407,000		261,000
Balance (in Dollars per share)		$ 71.34		$ 71.31		$ 61.65
Granted (restricted stock and stock units)	131,702	132,000		0		154,000
Granted (restricted stock and stock units) (in Dollars per share)	$ 85.80	$ 85.80		$ 0		$ 87.55
Vested		(150,000)	[1]	(14,000)	[2]	0
Vested (in Dollars per share)		$ 62.34	[1]	$ 69.02	[2]	$ 0
Canceled/forfeited		(7,000)		(10,000)		(8,000)
Canceled/forfeited (in Dollars per share)		$ 81.38		$ 77.13		$ 69.41
Balance		358,000		383,000		407,000
Balance (in Dollars per share)		$ 80.43		$ 71.34		$ 71.31

[1] Of the total 149,741 restricted stock awards that vested during fiscal 2013, 87,758 related to awards granted on October 23, 2009. These restricted stock awards cliff vested 60% after three years (on October 23, 2012) and the remaining 40% will vest after five years (on October 23, 2014). An additional 55,572 awards that vested in fiscal 2013 related to awards granted on February 9, 2010 at a price of $63.09. These restricted stock awards cliff vested 100% after three years (on February 9, 2013). The remaining 6,411 restricted stock awards that vested were previously granted between June 2010 and July 2011 and vesting occured when certain ASV targets were met in fiscal 2013.

[2] * Between June 2010 and July 2011, FactSet granted 21,102 restricted stock units which entitled the holder to shares of common stock as the awards vest. A restricted stock unit is a promise to deliver shares to the employee at a future date if certain vesting conditions are met. These restricted stock units are performance-based and cliff vest 25% when certain ASV targets are met. Of the total 21,102 units granted, 14,258 units vested during the fourth quarter of fiscal 2012 because FactSet achieved three of the four ASV growth targets.