Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($)	6 Months Ended
	Jan. 31, 2017	Jul. 31, 2016
Indefinite-lived Intangible Assets [Line Items]
Goodwill impairment	$ 0
Goodwill	228,700,000	$ 229,300,000
Intangible assets, net	40,100,000	$ 38,500,000
Amortization of existing intangible assets	2,900,000
Partmo
Indefinite-lived Intangible Assets [Line Items]
Amount of finite-lived intangibles acquired	$ 4,700,000
Customer Relationships | Partmo
Indefinite-lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	20 years
Trade Names | Partmo
Indefinite-lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	10 years