Basis of Presentation (Details) - USD ($) $ in Millions		3 Months Ended
	Jun. 01, 2018	Aug. 31, 2018	Aug. 31, 2017	May 31, 2018
New accounting pronouncements adopted
Accounts receivable, net	$ 170.6	$ 191.0		$ 202.0
Inventories	443.4	467.7		460.7
Contract assets-current	49.6	48.8
Other current assets	25.3	34.5		26.2
Other non-current assets	99.9	90.7		118.9
Accrued liabilities	147.4	110.8		138.3
Deferred tax liabilities	9.1	11.0		15.7
Other liabilities and deferred income	61.1	73.5		62.2
Retained earnings	712.8	725.2		$ 733.2
Sales		466.3	$ 397.9
Cost of sales		395.1
Gross profit (loss)		71.2	61.6
Provision for income taxes		2.3	4.4
Income from continuing operations		18.9	$ 11.0
ASC 606 Adjustments
New accounting pronouncements adopted
Accounts receivable, net	(31.4)
Inventories	(17.3)
Contract assets-current	49.6
Other current assets	(0.9)
Other non-current assets	(19.0)
Accrued liabilities	9.1
Deferred tax liabilities	(6.6)
Other liabilities and deferred income	(1.1)
Retained earnings	(20.4)
ASC 606 Adjustments | Other contracts
New accounting pronouncements adopted
Retained earnings	22.1
ASC 606 Adjustments | Repair services
New accounting pronouncements adopted
Retained earnings	1.3
ASC 606 Adjustments | Manufacturing products
New accounting pronouncements adopted
Retained earnings	0.4
ASU 2014-09 | ASC 606 Adjustments
New accounting pronouncements adopted
Accounts receivable, net		26.3
Inventories		20.0
Contract assets-current		(48.8)
Other current assets		0.9
Other non-current assets		19.4
Accrued liabilities		(11.4)
Deferred tax liabilities		6.6
Other liabilities and deferred income		4.6
Retained earnings		18.0
Sales		(4.8)
Cost of sales		(1.6)
Gross profit (loss)		(3.2)
Provision for income taxes		(0.8)
Income from continuing operations		(2.4)
ASU 2014-09 | Balances Excluding ASC 606
New accounting pronouncements adopted
Accounts receivable, net		217.3
Inventories		487.7
Other current assets		35.4
Other non-current assets		110.1
Accrued liabilities		99.4
Deferred tax liabilities		17.6
Other liabilities and deferred income		78.1
Retained earnings		743.2
Sales		461.5
Cost of sales		393.5
Gross profit (loss)		68.0
Provision for income taxes		3.1
Income from continuing operations		$ 16.5
ASU 2017-07 | Other income, net
New accounting pronouncements adopted
Pension income	$ 0.3