Fair Value Measurements (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Fair Value Measurements [Abstract]
Balance, beginning of period	$ 6,300	$ 4,200	$ 6,300	$ 2,000
Purchases				2,200
Rafael Spin-Off	(6,300)		(6,300)
Balance, end of period		4,200		4,200
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the period