Note 13. Employee Stock Option and Retirement Plans (Detail) (USD $)	0 Months Ended		1 Months Ended			3 Months Ended				6 Months Ended							3 Months Ended			14 Months Ended	3 Months Ended						6 Months Ended							1 Months Ended		1 Months Ended	12 Months Ended					3 Months Ended		6 Months Ended
	Jan. 15, 2013	Jan. 13, 2012	Nov. 30, 2012	Jul. 31, 2012	Nov. 30, 2011	Feb. 28, 2013		Nov. 30, 2012	Feb. 29, 2012	Feb. 28, 2013	Feb. 29, 2012	Aug. 31, 2012	Dec. 16, 2008	Feb. 28, 2013 In-The-Money Stock Options [Member]	Aug. 31, 2012 In-The-Money Stock Options [Member]	Feb. 28, 2013 November 2011 Annual Employee Performance-based Option Grant Review [Member]	Feb. 28, 2013 July 2012 Performance Based Option Grant Review [Member]	Feb. 28, 2013 Other Performace-Based Options [Member]	Aug. 31, 2012 Other Performace-Based Options [Member]	Jul. 31, 2011 Other Performace-Based Options [Member]	Nov. 30, 2012 Restricted Stock [Member]	Nov. 30, 2012 Awards Granted October 31, 2009 [Member]	Nov. 30, 2012 November 2010 Employee Restricted Stock Award [Member]	Nov. 30, 2012 Awards Granted Between June 2010 and July 2011 [Member]	Feb. 28, 2013 Employee Stock Purchase Plan [Member]	Feb. 29, 2012 Employee Stock Purchase Plan [Member]	Feb. 28, 2013 Employee Stock Purchase Plan [Member]	Feb. 29, 2012 Employee Stock Purchase Plan [Member]	Feb. 28, 2013 Granted Without Performance Conditions [Member] Minimum [Member]	Feb. 28, 2013 Granted Without Performance Conditions [Member] Maximum [Member]	Feb. 28, 2013 Majority of Options Granted with Performance Conditions [Member] Minimum [Member]	Feb. 28, 2013 Majority of Options Granted with Performance Conditions [Member] Maximum [Member]	Feb. 28, 2013 November 2011 Annual Employee Performance-based Option Grant Review [Member]	Nov. 30, 2012 November 2010 Annual Employee Performance-based Option Grant Review [Member]	Feb. 28, 2013 November 2010 Annual Employee Performance-based Option Grant Review [Member]	Jun. 30, 2010 Other Performace-Based Options [Member]	Aug. 31, 2011 Oct 2009 Annual Employee Performance-Based Option Grant Review [Member] Additional Stock-Based Compensation [Member]	Feb. 28, 2013 Financial Performance Level One [Member]	Feb. 28, 2013 Financial Performance Level Two [Member]	Feb. 28, 2013 Financial Performance Level Three [Member]	Feb. 28, 2013 Financial Performance Level Four [Member]	Feb. 28, 2013 Employee Stock Purchase Plan [Member]	Nov. 30, 2011 Employee Stock Purchase Plan [Member]	Feb. 28, 2013 Employee Stock Purchase Plan [Member]	Feb. 29, 2012 Employee Stock Purchase Plan [Member]
Stock Option Expiration Term																													7 years	10 years	7 years	10 years
Stock Option Vesting Rate After First Year of Grant Date										20.00%
Stock Option Vesting Rate Per Month from Two Years through Five Years of Grant Date										1.67%
Stock Option Vesting Rate for First Two Years for Grant Date										40.00%
Stock Option Vesting Rate Per Month from Three Years through Five Years										1.67%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)	18,781	20,976	1,011,510	241,546	665,551					1,656,185										204,508																746,415
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit (in Dollars per share)										$ 92.22
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number														3,300,000	2,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in Dollars per share)														$ 56.28	$ 48.17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value (in Dollars)														$ 134,800,000	$ 125,400,000
Share-Based Compensation Arrangement by Share-Based Payment Award Options Closing Share Price (in Dollars per share)						$ 97.29				$ 97.29
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value (in Dollars)						18,500,000			7,200,000	30,200,000	18,500,000
Vesting Percentage																																						0.00%	20.00%	60.00%	100.00%
ASV Growth Rate										6.30%
Percent of Performance-Based Stock Options Expected to Vest						20.00%																											0.00%	20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number			682					682				205					48,309	7,964																	202,302
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in Dollars)						49,100,000				49,100,000						4,300,000	1,300,000
Performance Measurement Period				5 years
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition										3 years 6 months							2 years 6 months
Share-based Compensation (in Dollars)										26,373,000	11,925,000							100,000																			15,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period						56,000	[1]	93,000		148,969									133,958		56,254			682
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period						(1,000)		(1,000)										9,301
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$ 24.23	$ 24.79																				$ 63.09			$ 15.18	$ 15.97	$ 15.44	$ 15.69
Vesting Rate Of Restricted Stock Awards After Three Years																							100.00%
Common Stock, Capital Shares Reserved for Future Issuance (in Shares)													500,000												155,560		155,560
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in Shares)										780,000	364,000														21,389	19,690	39,491	42,856														21,389	19,690	39,491	42,856
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)						$ 78.56																																					$ 74.29	$ 78.55	$ 73.95
Defined Contribution Plan, Employer Discretionary Contribution Amount (in Dollars)										$ 3,700,000	$ 3,100,000

[1] Of the total 56,254 restricted stock awards that vested during the second quarter of fiscal 2013, 55,572 related to awards granted on February 9, 2010 at the grant date price of $63.09. These restricted stock awards cliff vest 100% after three years (on February 9, 2013). The awards were amortized to expense over the vesting period using the straight-line attribution method. The remaining 682 restricted stock awards that vested during the second quarter of fiscal 2013 were previously granted in July 2011. These restricted stock units were performance-based and cliff vest when certain ASV targets are met. Of the total units originally granted, 205 units vested during the first quarter of fiscal 2013 and 682 vested during the second quarter of fiscal 2013 because FactSet achieved two of the three ASV growth targets. As of February 28, 2013, unamortized stock-based compensation expense of less than $0.1 million is to be amortized to compensation expense over the remaining vesting period.