Derivatives and Hedging Activities Notional Value of Derivatives Outstanding (Details) - USD ($) $ in Thousands	6 Months Ended
	Jan. 31, 2021	Jul. 31, 2020
Derivative [Line Items]
Document Period End Date	Jan. 31, 2021
Derivative, Notional Amount	$ 15,727	$ 27,707
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	12,300	24,600
Not designated as hedging Instruments [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 3,427	$ 3,107