CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (9,627)	$ (10,333)	$ (28,745)	$ 44,248
Other comprehensive income (loss):
Foreign currency translation adjustment	(608)	(1,411)	(276)	2,515
Net unrealized holding gain (loss) on securities, net of tax	3	(26)	(86)	(10)
Pension liability adjustments, net of tax	0	0	(64)	26
Other comprehensive gain (loss)	(605)	(1,437)	(426)	2,531
Comprehensive income (loss)	$ (10,232)	$ (11,770)	$ (29,171)	$ 46,779