Loss contingency product liability claim reserve.

No definition available.

Name:	msa_LossContingencyProductLiabilityClaimReserve
Namespace Prefix:	msa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loss Contingency, Years of Activity

+ References

No definition available.

+ Details

Name:	msa_LossContingencyYearsofActivity
Namespace Prefix:	msa_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum number of insurance carriers.

+ References

No definition available.

+ Details

Name:	msa_MinimumNumberOfInsuranceCarriers
Namespace Prefix:	msa_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in insurance settlements receivable, which are amounts due in settlement of a claim for reimbursement from an insurance company when the Company has suffered a loss covered under an insurance policy. The expectation is that such reimbursement will be received within one year of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

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

- Definition

Amount due in settlement of a claim for reimbursement from an insurance company when the Company has suffered a loss covered under an insurance policy.

+ References

No definition available.

+ Details

Name:	us-gaap_InsuranceSettlementsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount due in settlement of a claim for reimbursement from an insurance company when the Company has suffered a loss covered under an insurance policy. For classified balance sheets, represents the current amount receivable, that is amounts expected to be collected within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.8)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_InsuranceSettlementsReceivableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount due after one year of the balance sheet date (or one operating cycle, if longer) of amount due in settlement of a claim for reimbursement from an insurance company when the Company has suffered a loss covered under an insurance policy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_InsuranceSettlementsReceivableNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of judgment or settlement awarded to (against) the entity in respect of litigation.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Present value of the estimated aggregate accrual for damages arising from third-party use of the entity's product(s) or process(es) as of the balance sheet date (if the accrual qualifies for discounting).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.Y.Q1)

-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section Y

-Paragraph Question 1

+ Details

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

- Definition

Number of pending claims pertaining to a loss contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

+ Details

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of loss reported during the period pertaining to product liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

+ Details

Name:	us-gaap_ProductLiabilityAccrualPeriodExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=msa_CumulativeTraumaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=msa_SingleIncidentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=msa_UninsuredCumulativeTraumaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
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Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended			4 Months Ended
	Dec. 31, 2014 Vendor LegalMatter	Dec. 31, 2013 LegalMatter	Dec. 31, 2012	Jan. 31, 2015	Dec. 31, 2011 LegalMatter
Loss Contingencies [Line Items]
Number of lawsuits	2,326	2,840	2,609		2,321
Years of Activity	5 years
Number of insurance carriers	20msa_MinimumNumberOfInsuranceCarriers
Increase (decrease) in insurance settlements receivable		$ 95.7
Insurance receivables	220.5us-gaap_InsuranceSettlementsReceivable	124.8us-gaap_InsuranceSettlementsReceivable	130.0us-gaap_InsuranceSettlementsReceivable		112.1us-gaap_InsuranceSettlementsReceivable
Insurance receivable, current	2.0
Insurance receivable, noncurrent	218.5	124.8
Single Incident
Loss Contingencies [Line Items]
Reserves for product liability claims	3.5	4.0
Cumulative Trauma
Loss Contingencies [Line Items]
Loss contingency accrual, product liability, net	74.9	5.6
Product Liability Expense	169.6	169.6	169.6
Uninsured Cumulative Trauma
Loss Contingencies [Line Items]
Product Liability Expense	3.9	1.7	2.1
Other Noncurrent Liabilities \| Cumulative Trauma
Loss Contingencies [Line Items]
Loss contingency accrual, product liability, net	35.1
Subsequent Event \| Cumulative Trauma
Loss Contingencies [Line Items]
Litigation settlement amount				$ 71.8