Segment Information - Net Income Reconciliation (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total profit from reportable segments	$ 50,399	$ 48,495	$ 107,067	$ 107,501
Unallocated amounts:
Administrative costs	(26,810)	(26,805)	(53,376)	(54,561)
Restructuring charges	0	(4,879)	0	(9,157)
Investment and other income	(992)	211	(1,751)	535
Interest expense	(2,130)	(3,000)	(4,281)	(5,891)
Earnings from continuing operations before income taxes	$ 20,467	$ 14,022	$ 47,659	$ 38,427