XML 106 R92.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Pensions and Other Post-retirement Benefits - Schedule of Expected Return on Assets for Net Periodic Pension Cost (Detail) | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
Pension Plan Assets at December 31, | 100.00% | 100.00%
Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension Plan Assets at December 31, | 57.00% | 70.00%
Fixed income securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension Plan Assets at December 31, | 26.00% | 20.00%
Pooled investment funds |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension Plan Assets at December 31, | 12.00% | 5.00%
Insurance contracts |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension Plan Assets at December 31, | 3.00% | 4.00%
Cash and cash equivalents |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Pension Plan Assets at December 31, | 2.00% | 1.00%

X
- 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
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2446-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=msa_PooledInvestmentFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=msa_InsuranceContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |