Note 13. Employee Stock Option and Retirement Plans (Detail) (USD $)	1 Months Ended			3 Months Ended								1 Months Ended	3 Months Ended		14 Months Ended	3 Months Ended												3 Months Ended					1 Months Ended		12 Months Ended
	Nov. 30, 2012	Jul. 31, 2012	Nov. 30, 2011	Nov. 30, 2012		Nov. 30, 2011	Aug. 31, 2012	Dec. 16, 2008	Nov. 30, 2012 In-The-Money Stock Options [Member]	Aug. 31, 2012 In-The-Money Stock Options [Member]	Nov. 30, 2012 November 2011 Annual Employee Performance-based Option Grant Review [Member]	Nov. 30, 2012 July 2012 Performance Based Option Grant Review [Member]	Nov. 30, 2012 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]	Nov. 30, 2012 Employee Stock Purchase Plan [Member]	Nov. 30, 2011 Employee Stock Purchase Plan [Member]	Nov. 30, 2012 Employee Stock Purchase Plan [Member]	Nov. 30, 2011 Employee Stock Purchase Plan [Member]	Nov. 30, 2012 Financial Performance Level One [Member]	Nov. 30, 2012 Financial Performance Level Two [Member]	Nov. 30, 2012 Financial Performance Level Three [Member]	Nov. 30, 2012 Financial Performance Level Four [Member]	Nov. 30, 2012 Minimum [Member] Granted Without Performance Conditions [Member]	Nov. 30, 2012 Minimum [Member] Majority of Options Granted with Performance Conditions [Member]	Nov. 30, 2012 Maximum [Member] Granted Without Performance Conditions [Member]	Nov. 30, 2012 Maximum [Member] Majority of Options Granted with Performance Conditions [Member]	Nov. 30, 2012 November 2011 Annual Employee Performance-based Option Grant Review [Member]	Nov. 30, 2012 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]
Stock Option Expiration Term																												7 years	7 years	10 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)	1,011,510	241,546	665,551	1,646,818											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									2,700,000	2,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in Dollars per share)									$ 49.10	$ 48.17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value (in Dollars)									$ 117,600,000	$ 125,400,000
Share-Based Compensation Arrangement by Share-Based Payment Award Options Closing Share Price (in Dollars per share)	$ 92.39			$ 92.39
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value (in Dollars)				11,700,000		11,300,000
Vesting Percentage																			25.00%					0.00%	20.00%	60.00%	100.00%
ASV Growth Rate				7.00%
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	4,957			4,957			14,258					48,309	14,605																				202,302
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in Dollars)	53,700,000			53,700,000							4,600,000	1,400,000				3,200,000
Performance Measurement Period		5 years
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition				3 years 255 days								2 years 292 days				1 year 328 days
Share-based Compensation (in Dollars)				5,203,000		5,880,000							200,000							300,000	400,000														15,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				92,715	[1]								46,644	133,958		92,715	87,758		4,957
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				(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)																	$ 66.46			$ 15.74	$ 15.46
Vesting Rate Of Restricted Stock Awards After Three Years																		60.00%
Vesting Rate Of Restricted Stock Awards After Five Years																		40.00%
Common Stock, Capital Shares Reserved for Future Issuance (in Shares)								500,000												176,949
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in Shares)				333,000		209,000														18,102	23,166	18,102	23,166
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)				$ 78.53																			$ 73.66
Defined Contribution Plan, Employer Discretionary Contribution Amount (in Dollars)				$ 1,800,000		$ 1,400,000

[1] Of the total 92,715 restricted stock awards that vested during the first quarter of fiscal 2013, 87,758 related to awards granted on October 23, 2009 at the grant date price of $66.46. These restricted stock awards cliff vest 60% after three years (on October 23, 2012) and the remaining 40% after five years (October 23, 2014). The awards are amortized to expense over the vesting period using the straight-line attribution method. As of November 30, 2012, unamortized stock-based compensation expense of $3.2 million is to be amortized to compensation expense over the remaining vesting period of 1.9 years. The remaining 4,957 restricted stock awards that vested during the first quarter of fiscal 2013 were previously granted between June 2010 and July 2011. These restricted stock units were performance-based and cliff vest 25% when certain ASV targets are met. Of the total units originally granted, 14,258 units vested during the fourth quarter of fiscal 2012 and the remaining 4,957 vested during the first quarter of fiscal 2013 because FactSet achieved all four ASV growth targets. As of November 30, 2012, there is no remaining unamortized stock-based compensation expense as all units vested.