Intangible Assets (Details) - USD ($)	3 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Jul. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 400,509,000		$ 400,509,000
Accumulated amortization	143,825,000		138,619,000
Net carrying amount	256,684,000		261,890,000
Amortization of intangibles	5,206,000	$ 4,289,000
Amortization expense - year one	20,700,000
Amortization expense - year two	19,563,000
Amortization expense - year three	18,322,000
Amortization expense - year four	18,322,000
Amortization expense - year five	$ 17,631,000
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	20 years 6 months	20 years 6 months
Gross carrying amount	$ 276,834,000		276,834,000
Accumulated amortization	69,694,000		66,484,000
Net carrying amount	$ 207,140,000		210,350,000
Technologies
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	12 years 8 months 12 days	12 years 8 months 12 days
Gross carrying amount	$ 92,649,000		92,649,000
Accumulated amortization	60,948,000		59,522,000
Net carrying amount	$ 31,701,000		33,127,000
Trademarks and other
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	16 years 8 months 12 days	16 years 8 months 12 days
Gross carrying amount	$ 31,026,000		31,026,000
Accumulated amortization	13,183,000		12,613,000
Net carrying amount	$ 17,843,000		$ 18,413,000