Stock Plans - Additional Information (Detail)	6 Months Ended
Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options expiration period	10 years
Stock options exercisable period after grant date	3 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award based on achieving specified performance targets	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award based on achieving specified performance targets	200.00%
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vest period	3 years

Percentage of target award based on achieving a targeted return on net assets based on which final number of shares to be issued for performance stock units.

No definition available.

+ Details

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Namespace Prefix:	msa_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock options exercisable, years.

+ References

No definition available.

+ Details

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

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

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