Segment Information Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 77,209	$ 694,087	$ 924,638	$ 267,770	$ 244,006	$ 957,987	$ 849,578	$ 220,004	$ 1,963,704	$ 2,271,575	$ 2,011,553
Property, Plant and Equipment, Net	2,192,679				1,842,500				2,192,679	1,842,500
Canadian [Member]
Segment Reporting Information [Line Items]
Revenues									223,300	308,100	321,000
Property, Plant and Equipment, Net	291,700				319,400				291,700	319,400
Geographic Distribution, Foreign [Member]
Segment Reporting Information [Line Items]
Revenues									307,743	406,513	401,230
Property, Plant and Equipment, Net	432,987				461,122				432,987	461,122
Geographic Distribution, Domestic [Member]
Segment Reporting Information [Line Items]
Revenues									1,655,961	1,865,062	$ 1,610,323
Property, Plant and Equipment, Net	$ 1,759,692				$ 1,381,378				$ 1,759,692	$ 1,381,378