Earnings Per Share - Reconciliation of Shares Used to Calculate Basic and Diluted Earnings Per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Class A Common Stock
Class of Stock [Line Items]
Basic shares (shares)	25,824,194	25,761,733	25,805,981	25,729,623
Assumed conversion of stock options (shares)	4,688	4,876	4,679	4,301
Diluted shares (shares)	25,828,882	25,766,609	25,810,660	25,733,924
Class B Common Stock
Class of Stock [Line Items]
Basic shares (shares)	22,000,000	22,100,000	22,000,000	22,100,000
Diluted shares (shares)	22,000,000	22,100,000	22,000,000	22,100,000
Basic and diluted shares (shares)	22,009,725	22,108,942	22,009,725	22,114,454