Earnings Per Share - Reconciliation of Shares Used to Calculate Basic and Diluted Earnings Per Share (Details) - shares	3 Months Ended								12 Months Ended
	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Class A common stock
Class of Stock [Line Items]
Basic (shares)	26,441,986	26,441,986	26,386,439	26,260,943	26,257,943	26,257,943	26,250,460	25,991,433	26,382,838	26,189,445	25,915,887
Assumed conversion of stock options and unvested shares (shares)									7,805	25,666	49,969
Diluted (shares)	26,512,331	26,442,595	26,386,439	26,414,280	26,360,148	26,257,943	26,255,112	25,991,433	26,390,643	26,215,111	25,965,856
Class B common stock
Class of Stock [Line Items]
Basic (shares)	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,000,000.0	22,000,000.0	22,000,000.0
Diluted (shares)	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,007,725	22,000,000.0	22,000,000.0	22,000,000.0
Basic and diluted shares (shares)									22,007,725	22,007,725	22,007,725