Consolidated Statements of Operations Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2014
Loss from discontinued operations tax benefit	$ 0.0	$ 0.6	$ (0.4)
Discontinued operations, loss from operations net of tax	$ 0.0	$ 0.9	$ (0.6)

Discontinued operations, loss from operations net of tax includes after-tax loss from operating activities incurred during the period.

No definition available.

Name:	omn_DiscontinuedOperationsLossFromOperationsNetOfTax
Namespace Prefix:	omn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration