Summary of Significant Accounting Policies (Narrative) (Details)	3 Months Ended								12 Months Ended
	Jul. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Jul. 31, 2017 USD ($)	Apr. 30, 2017 USD ($)	Jan. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)	Jul. 31, 2018 USD ($) joint_venture plant	Jul. 31, 2017 USD ($)	Jul. 31, 2016 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of manufacturing plants around world | plant									43
Number of joint ventures | joint_venture									3
Foreign currency transaction gains (losses)									$ (7,400,000)	$ (4,000,000)	$ (4,700,000)
Number of days considered to review for collectability									90 days
Percentage of LIFO inventory	28.00%				27.20%				28.00%	27.20%
Excess of FIFO over LIFO inventory	$ 38,200,000				$ 37,100,000				$ 38,200,000	$ 37,100,000
Depreciation									71,100,000	68,800,000	68,800,000
Cost of sales									1,798,700,000	1,548,800,000	1,465,500,000
Increase in net cash provided by operating activities									262,900,000	317,800,000	291,300,000
Increase in net cash used in financing activities									(268,800,000)	(165,200,000)	(180,200,000)
Net sales	$ 724,700,000	$ 700,000,000	$ 664,700,000	$ 644,800,000	$ 660,100,000	$ 608,200,000	$ 550,600,000	$ 553,000,000	2,734,200,000	2,371,900,000	2,220,300,000
Operating income									$ 380,000,000	328,600,000	274,200,000
Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Capitalization of direct cost, amortization period in years									5 years
Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Capitalization of direct cost, amortization period in years									7 years
Machinery and equipment | Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Finite-lived intangible assets, useful life									3 years
Machinery and equipment | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Finite-lived intangible assets, useful life									10 years
Building and Building Improvements | Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Finite-lived intangible assets, useful life									10 years
Building and Building Improvements | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Finite-lived intangible assets, useful life									40 years
Other Intangible Assets | Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Finite-lived intangible assets, useful life									3 years
Other Intangible Assets | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Finite-lived intangible assets, useful life									20 years
Partially Completed Facility In Xuzhou China
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Asset impairment charges									$ 0	0	2,900,000
Accounting Standards Update 2016-09
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Increase in net cash provided by operating activities										7,500,000	5,200,000
Increase in net cash used in financing activities										7,500,000	5,200,000
Accounting Standards Update 2014-09
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cost of sales									21,900,000
Net sales									21,900,000
Accounting Standards Update 2017-07
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Operating income									3,000,000	5,000,000
Shipping and handling
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cost of sales									$ 73,500,000	$ 61,400,000	$ 56,300,000