Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive (Loss) Income, Balance, beginning			$ (4,117)
Other comprehensive loss before reclassifications, net of tax			(94)
Amounts reclassified from accumulated other comprehensive income, net of tax			53
Net current-period other comprehensive income (loss), net of tax	$ 34	$ (337)	41	$ (737)
Accumulated Other Comprehensive (Loss) Income, Balance, ending	(4,158)		(4,158)
Pension and Postretirement Health Benefits
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive (Loss) Income, Balance, beginning			(4,428)
Other comprehensive loss before reclassifications, net of tax			0
Amounts reclassified from accumulated other comprehensive income, net of tax			53
Net current-period other comprehensive income (loss), net of tax			(53)
Accumulated Other Comprehensive (Loss) Income, Balance, ending	(4,375)		(4,375)
Cumulative Translation Adjustment
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive (Loss) Income, Balance, beginning			311
Other comprehensive loss before reclassifications, net of tax			(94)
Amounts reclassified from accumulated other comprehensive income, net of tax			0
Net current-period other comprehensive income (loss), net of tax			94
Accumulated Other Comprehensive (Loss) Income, Balance, ending	$ 217		$ 217