Changes in Accumulated Other Comprehensive (Loss) Income (Detail) $ in Thousands	9 Months Ended
	Apr. 30, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 460,494
Pre-tax change before reclassification to earnings	3,200
Amount reclassified to earnings	(800)
Ending balance	483,188
Unrealized Losses on Available For Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(10)
Pre-tax change before reclassification to earnings	(200)
Ending balance	(200)
Unrealized Gain (Loss) on Foreign Currency Forward Contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	500
Amount reclassified to earnings	(800)
Income tax benefit (provision)	200
Ending balance	(100)
Unrealized Gains (Losses) on Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(3,500)
Pre-tax change before reclassification to earnings	200
Income tax benefit (provision)	(100)
Ending balance	(3,400)
Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(2,100)
Pre-tax change before reclassification to earnings	3,200
Income tax benefit (provision)	(100)
Ending balance	1,000
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(5,100)
Ending balance	$ (2,700)