Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Income Taxes [Line Items]
U.S. Federal statutory tax rate	35.00%	35.00%	35.00%
Discrete tax benefit	$ 2.9	$ 12.9
Reduction in uncertain tax positions associated with expiration of statute of limitations	3.4
Remeasurement of tax reserves on a reduction in uncertain federal tax credits for R&D	0.8	1.0
Provision on reduction of domestic production deduction due to NOL carryback claim	0.3
Other items	1.0	0.4
Reduction of taxes from change in classification of Canadian operations		8.8
Discrete tax items, deduction for historical currency losses		2.7
Undistributed earnings of consolidated foreign subsidiaries	79.1
Unrecognized tax benefits	4.7	6.9	$ 7.3
Unrecognized tax benefits that would impact effective tax rate	2.5
Unrecognized tax benefits, interest on income taxes expense	0.3
Reduction in uncertain tax benefits and accrued interest	3.4
Unrecognized tax benefits, accrued interest and penalties	0.3	0.6
Deferred tax assets current	8.0	9.3
Refundable income tax assets current	10.4	$ 9.3
BELGIUM
Income Taxes [Line Items]
Net operating loss carryforwards, not subject to expiration	3.0
UNITED KINGDOM
Income Taxes [Line Items]
Net operating loss carryforwards, not subject to expiration	3.0
DENMARK
Income Taxes [Line Items]
Net operating loss carryforwards, not subject to expiration	0.1
CANADA
Income Taxes [Line Items]
Net operating loss carryforwards, subject to expiration	$ 1.3
Net operating loss carryforwards, expiration year	2024
Tax credit carryforwards	$ 7.5
Tax credit carryforwards, expiration year	2025
UNITED STATES
Income Taxes [Line Items]
Net operating loss carryforwards, subject to expiration	$ 0.4
Net operating loss carryforwards, expiration year	2025
State and Local Jurisdiction
Income Taxes [Line Items]
Tax credit carryforwards	$ 13.5
Tax credit carryforwards, expiration year	2021
LUXEMBOURG
Income Taxes [Line Items]
Net operating loss carryforwards, subject to expiration	$ 13.6