Stock Compensation Plans - Additional Information (Detail) (USD $)	12 Months Ended			12 Months Ended														12 Months Ended																3 Months Ended			12 Months Ended
	Oct. 31, 2012	Feb. 28, 2011	Feb. 17, 2005	Oct. 31, 2012 Management Retainer and Meeting Fees	Oct. 31, 2012 Other Participants Base Salary Compensation	Oct. 31, 2012 Other Participants Deferred Bonus	Oct. 31, 2012 Stock Repurchase Plan	Oct. 31, 2011 Stock Repurchase Plan	Oct. 31, 2010 Stock Repurchase Plan	Oct. 31, 2012 Restricted Stock Units (RSUs)	Oct. 31, 2011 Restricted Stock Units (RSUs)	Oct. 31, 2010 Restricted Stock Units (RSUs)	Oct. 31, 2009 Restricted Stock Units (RSUs)	Oct. 31, 2008 Restricted Stock Units (RSUs)	Oct. 31, 2007 Restricted Stock Units (RSUs)	Feb. 28, 2011 Restricted Stock Units (RSUs)	Feb. 17, 2005 Restricted Stock Units (RSUs)	Oct. 31, 2011 Stock Option	Oct. 31, 2012 Restricted Stock	Oct. 31, 2011 Restricted Stock	Oct. 31, 2010 Restricted Stock	Oct. 31, 2012 Restricted Stock Stock Repurchase Plan	Oct. 31, 2011 Restricted Stock Stock Repurchase Plan	Oct. 31, 2010 Restricted Stock Stock Repurchase Plan	Oct. 31, 2012 Restricted Stock Stock Repurchase Plan Employer Matched Contribution	Oct. 31, 2011 Restricted Stock Stock Repurchase Plan Employer Matched Contribution	Oct. 31, 2010 Restricted Stock Stock Repurchase Plan Employer Matched Contribution	Oct. 31, 2012 Restricted Stock Minimum	Oct. 31, 2011 Restricted Stock Minimum	Oct. 31, 2010 Restricted Stock Minimum	Oct. 31, 2012 Restricted Stock Maximum	Oct. 31, 2011 Restricted Stock Maximum	Oct. 31, 2010 Restricted Stock Maximum	Apr. 30, 2012 Performance Based Awards	Jan. 31, 2011 Performance Based Awards	Jan. 31, 2010 Performance Based Awards	Oct. 31, 2011 Performance Based Awards	Oct. 31, 2010 Performance Based Awards	Jan. 31, 2012 Performance Based Awards	Jan. 31, 2009 Performance Based Awards	Jan. 31, 2008 Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation plan, maximum shares that may be issued		3,500,000	2,250,000													1,562,500	562,500																		86,725	70,000			95,175	60,500	67,820
Stock compensation plan, vesting period																		4 years				3 years						3 years	3 years	3 years	4 years	4 years	4 years
Compensation cost																			$ 4,584,000	$ 3,816,000	$ 4,055,000																$ 1,485,000	$ 3,190,000
Restricted stock awards vested										81,819	35,193	96,838	9,000	21,000	0				243,850
Shares withheld to satisfy tax withholding obligations of recipients																			63,286
Unrecognized share-based compensation costs																			7,400,000
Unrecognized share-based compensation costs weighted average period of recognition																			1 year 6 months
Share Purchase Plan, percentage compensation received in the form of restricted stock				100.00%	15.00%	75.00%
Share Purchase Plan, company's matched contributions	25.00%
Share Purchase Plan, shares of restricted stock issued																						16,359	21,497	22,081	4,005	5,277	5,437
Share Purchase Plan, value per share of restricted issued																						$ 48.13	$ 43.97	$ 46.38	$ 48.13	$ 43.97	$ 46.37
Share Purchase Plan, compensation expense related to the matching contribution							197,000	201,000	273,000
Performance share agreements, performance period																																		2 years	2 years	2 years
Performance share agreements, percentage of grants made, minimum																																		50.00%	50.00%	50.00%
Performance share agreements, percentage of grants made, maximum																																		200.00%	200.00%	200.00%
Stock compensation plan, common Stock reserved for grant																		2,250,000
Stock compensation plan, term																		10 years
Options outstanding and exercisable, exercise price	$ 32.93
Options outstanding and exercisable, shares	6,000
Stock options exercised, intrinsic value	$ 197,600