Derivatives and Hedging Activities Notional Value of Derivatives Outstanding (Details) - USD ($) $ in Thousands	6 Months Ended
	Jan. 31, 2020	Jul. 31, 2019
Derivative [Line Items]
Document Period End Date	Jan. 31, 2020
Derivative, Notional Amount	$ 16,529	$ 29,389
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	13,046	26,013
Not designated as hedging Instruments [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 3,483	$ 3,376