Fixed Charge Coverage Ratio Required by Debt Covenant

No definition available.

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- Definition

Expansion feature included in the line of credit agreement, allowing the Company to increase its maximum borrowing capacity under the agreement at a later date.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Net Leverage Ratio Required by Debt Covenant

+ References

No definition available.

+ Details

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Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

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-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum amount borrowed under the credit facility at any time during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average interest rate of short-term debt outstanding calculated over time.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=omn_EurodollarRevolverDomain
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_ForeignLineOfCreditMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=omn_TermLoanBMember
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Debt and Credit Lines Additional Information (Details) € in Millions	3 Months Ended
	Feb. 29, 2020 USD ($)	Feb. 28, 2019 USD ($)	Feb. 29, 2020 EUR (€)	Feb. 29, 2020 USD ($)	Nov. 30, 2019 EUR (€)	Nov. 30, 2019 USD ($)
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate, over Time	4.97%	5.71%
Amortization of Debt Issuance Costs and Discounts	$ 400,000	$ 400,000
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Expiration Date	Aug. 26, 2021
Line of Credit Facility, Maximum Amount Outstanding During Period	$ 25,000,000.0
Fixed Charge Coverage Ratio Required by Debt Covenant			1.1	1.1
Long-term Line of Credit, Outstanding Borrowings				$ 22,000,000.0
Line of Credit Facility, Remaining Borrowing Capacity				33,800,000
Eurodollar Revolver [Domain]
Debt Instrument [Line Items]
Line of Credit Facility, Expansion Feature \| €			€ 9.0
Long-term Line of Credit, Outstanding Borrowings \| €			0.0
Line of Credit Facility, Remaining Borrowing Capacity \| €			16.7
Line of Credit Facility, Maximum Borrowing Capacity \| €			€ 25.0
Foreign Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Line of Credit, Outstanding Borrowings				0	€ 0.0
Line of Credit Facility, Maximum Borrowing Capacity				6,600,000		$ 12,100,000
Term Loan B [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 350,000,000.0
Net Leverage Ratio Required by Debt Covenant			5.0	5.0
Debt Instrument, Basis Spread on Variable Rate	3.25%
Line of Credit Facility, Expansion Feature				$ 120,000,000.0
Additional Term Loan [Member]
Debt Instrument [Line Items]
Net Leverage Ratio Required by Debt Covenant			4.0	4.0