Derivatives and Hedging - Derivatives Not Designated as Hedging Instruments (Details) £ in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
	Feb. 01, 2019 USD ($)	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Jan. 31, 2020 GBP (£)	Jul. 31, 2019 USD ($)
Derivative [Line Items]
Foreign currency transaction gain (loss)		$ 3,802		$ 2,843
Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount		34,093		34,093			$ 35,700
Foreign currency transaction gain (loss)	$ (70,777)
Derivative liability		1,446		1,446			$ 1,226
Not Designated as Hedging Instrument | Erwin Hymer Group
Derivative [Line Items]
Foreign currency transaction gain (loss)			$ (31,152)		$ (73,707)
Foreign Exchange Forward
Derivative [Line Items]
Notional amount		$ 32,824		$ 32,824		£ 25,000