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, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Class A Common Stock
Class of Stock [Line Items]
Basic shares (shares)	25,934,680	25,824,194	25,890,495	25,805,981
Assumed conversion of restricted shares (shares)	0	4,688	0	4,679
Diluted shares (shares)	25,934,680	25,828,882	25,890,495	25,810,660
Class B Common Stock
Class of Stock [Line Items]
Basic shares (shares)	22,000,000	22,000,000	22,000,000	22,000,000
Diluted shares (shares)	22,000,000	22,000,000	22,000,000	22,000,000
Basic and diluted shares (shares)	22,007,725	22,009,725	22,007,725	22,009,725