Derivatives and Hedging Activities Notional Value of Derivatives Outstanding (Details) - USD ($) $ in Thousands	9 Months Ended
	Apr. 30, 2020	Jul. 31, 2019
Derivative [Line Items]
Document Period End Date	Apr. 30, 2020
Derivative, Notional Amount	$ 24,240	$ 29,389
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	21,533	26,013
Not designated as hedging Instruments [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 2,707	$ 3,376