Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Income Taxes [Line Items]
U.S. Federal statutory tax rate (%)	35.00%	35.00%	35.00%
Discrete tax provisions (benefits)	$ (15.7)	$ 1.2
Increase in valuation allowance on deferred tax assets	16.6
Decrease in prepaid income taxes	0.8
Reduction in uncertain tax positions associated with expiration of statute of limitations	0.7	0.3
Increase (decrease) in uncertain tax positions primarily associated with the BK Medical matter	(0.4)	1.5
Decrease in uncertain tax positions associated with settlement of a transfer pricing audit	0.5
Other items	0.1	0.3
Federal tax credits for R&D		0.4
Undistributed earnings of consolidated foreign subsidiaries	57.4
Unrecognized tax benefits	6.3	7.6	$ 6.0
Unrecognized tax benefits that would impact effective tax rate	2.3
Unrecognized tax benefits, interest on income taxes expense	0.7
Reduction in uncertain tax benefits and accrued interest	1.8
Unrecognized tax benefits, accrued interest and penalties	0.1	0.4
Refundable income tax assets current	4.7	$ 3.0
UNITED STATES
Income Taxes [Line Items]
Net operating loss carryforwards, subject to expiration	$ 5.3
Net operating loss carryforwards, expiration year	2037
Tax credit carryforwards	$ 0.8
Tax credit carryforwards, expiration year	2027
BELGIUM
Income Taxes [Line Items]
Net operating loss carryforwards, not subject to expiration	$ 2.9
DENMARK
Income Taxes [Line Items]
Net operating loss carryforwards, not subject to expiration	9.8
CANADA
Income Taxes [Line Items]
Net operating loss carryforwards, subject to expiration	$ 4.9
Net operating loss carryforwards, expiration year	2024
Tax credit carryforwards	$ 2.8
Tax credit carryforwards, expiration year	2021
State and Local Jurisdiction
Income Taxes [Line Items]
Tax credit carryforwards	$ 15.2
Tax credit carryforwards, expiration year	2021
LUXEMBOURG
Income Taxes [Line Items]
Net operating loss carryforwards, subject to expiration	$ 16.2