Components of Net Periodic Benefit Cost (Details) - USD ($)	3 Months Ended			6 Months Ended	9 Months Ended
	Jan. 31, 2021	Jul. 31, 2020	Jul. 31, 2019	Apr. 30, 2020	Jul. 31, 2020	Jul. 31, 2019
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		$ 675,000	$ 843,000		$ 2,026,000	$ 2,525,000
Expected return on plan assets		(831,000)	(836,000)		(2,493,000)	(2,506,000)
Defined Benefit Plan, Amortization of Gain (Loss)		374,000	288,000		1,122,000	861,000
Net periodic (benefit) cost		218,000	295,000		655,000	880,000
Pension Contributions				$ 219,000
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		2,000	3,000		6,000	9,000
Expected return on plan assets		0	0		0	0
Defined Benefit Plan, Amortization of Gain (Loss)		2,000	1,000		6,000	4,000
Net periodic (benefit) cost		$ 4,000	$ 4,000		$ 12,000	$ 13,000
Forecast [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Contributions	$ 897,000