XML 92 R76.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Retirement Benefit Plans (Weighted Average Asset Allocations) (Details) - Pension Plans, Defined Benefit | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Hourly Employees’ Pension Plan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 0.00% | 100.00%
Hourly Employees’ Pension Plan | Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 0.00% | 55.00%
Hourly Employees’ Pension Plan | Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 0.00% | 37.00%
Hourly Employees’ Pension Plan | Short-term investments |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 0.00% | 3.00%
Hourly Employees’ Pension Plan | Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 0.00% | 5.00%
Employees’ Retirement Plan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 100.00% | 100.00%
Employees’ Retirement Plan | Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 54.00% | 55.00%
Employees’ Retirement Plan | Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 38.00% | 37.00%
Employees’ Retirement Plan | Short-term investments |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 3.00% | 3.00%
Employees’ Retirement Plan | Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset allocations as a percentage of plan assets | 5.00% | 5.00%

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=65897934&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=65897934&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_MultiemployerPlanNameAxis=alg_GradallCompanyHourlyEmployeesPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_ShortTermInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_OtherInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=alg_GradallCompanyEmployeesRetirementPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |