Segment Information Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 244,006	$ 957,987	$ 849,578	$ 220,004	$ 211,637	$ 844,491	$ 734,575	$ 220,850	$ 2,271,575	$ 2,011,553	$ 1,907,218
Property, Plant and Equipment, Net	1,842,500				1,627,219				1,842,500	1,627,219
Canadian [Member]
Segment Reporting Information [Line Items]
Revenues									308,100	321,000	257,800
Property, Plant and Equipment, Net	319,400				316,800				319,400	316,800
Geographic Distribution, Foreign [Member]
Segment Reporting Information [Line Items]
Revenues									406,513	401,230	328,942
Property, Plant and Equipment, Net	461,122				417,050				461,122	417,050
Geographic Distribution, Domestic [Member]
Segment Reporting Information [Line Items]
Revenues									1,865,062	1,610,323	$ 1,578,276
Property, Plant and Equipment, Net	$ 1,381,378				$ 1,210,169				$ 1,381,378	$ 1,210,169