Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income, Balance, beginning			$ (9,245)
Other comprehensive loss, before reclassifications, net of tax			(150)
Amounts reclassified from accumulated other comprehensive income, net of tax			308
Net current-period other comprehensive income (loss), net of tax	$ (9)	$ (259)	158	$ (359)
Accumulated Other Comprehensive Income, Balance, ending	(9,087)		(9,087)
Pension and Postretirement Health Benefits
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income, Balance, beginning			(8,975)
Other comprehensive loss, before reclassifications, net of tax			0
Amounts reclassified from accumulated other comprehensive income, net of tax			308
Net current-period other comprehensive income (loss), net of tax			308
Accumulated Other Comprehensive Income, Balance, ending	(8,667)		(8,667)
Cumulative Translation Adjustment
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income, Balance, beginning			(270)
Other comprehensive loss, before reclassifications, net of tax			(150)
Amounts reclassified from accumulated other comprehensive income, net of tax			0
Net current-period other comprehensive income (loss), net of tax			(150)
Accumulated Other Comprehensive Income, Balance, ending	$ (420)		$ (420)