Intangible Assets (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016	Jul. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 361,095,000		$ 361,095,000		$ 361,095,000
Accumulated amortization	93,956,000		93,956,000		76,401,000
Net carrying amount	267,139,000		267,139,000		$ 284,694,000
Amortization of intangibles	5,468,000	$ 4,776,000	17,555,000	$ 7,348,000
Amortization expense - year one	22,823,000		22,823,000
Amortization expense - year two	21,075,000		21,075,000
Amortization expense - year three	17,155,000		17,155,000
Amortization expense - year four	17,155,000		17,155,000
Amortization expense - year five	16,196,000		$ 16,196,000
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period			20 years 3 months 18 days		20 years 3 months 18 days
Gross carrying amount	249,831,000		$ 249,831,000		$ 249,831,000
Accumulated amortization	38,567,000		38,567,000		28,497,000
Net carrying amount	211,264,000		$ 211,264,000		$ 221,334,000
Technologies
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period			12 years 3 months 18 days		12 years 3 months 18 days
Gross carrying amount	82,370,000		$ 82,370,000		$ 82,370,000
Accumulated amortization	47,182,000		47,182,000		42,860,000
Net carrying amount	35,188,000		$ 35,188,000		$ 39,510,000
Trademarks and other
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period			16 years 4 months 22 days		16 years 3 months 18 days
Gross carrying amount	28,894,000		$ 28,894,000		$ 28,894,000
Accumulated amortization	8,207,000		8,207,000		5,044,000
Net carrying amount	$ 20,687,000		$ 20,687,000		$ 23,850,000