XML 18 R55.htm IDEA: XBRL DOCUMENT v2.4.1.9
Retirement Benefit Plans (Narrative) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Pension expense $ 11us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost $ (100)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
Supplemental Employee Retirement Plans, Defined Benefit    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Pension expense 150us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
140us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Requisite service period 10 years  
Percentage of final 3 year average salary in which retirement benefit is based (percentage) 20.00%alg_PercentageOfFinalThreeYearsAverageSalaryRetirementBenefitAssumption
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
 
Term of final average salary used to determine retirement benefit 3 years  
Retirement age 65 years  
Period after death or change in control benefit will be paid 90 days  
Maximum contractual term 15 years  
Gradall Company Hourly Employees Pension Plan    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Former employees covered by pension plan 333alg_FormerEmployeesCoveredByPensionPlan
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyHourlyEmployeesPensionPlanMember
 
Current employees covered in the Gradall Company Hourly Employees' Pension Plan who were formerly employed by former parent (Employees) 122alg_CurrentEmployeesCoveredByPensionPlan
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyHourlyEmployeesPensionPlanMember
 
Pension expense 0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyHourlyEmployeesPensionPlanMember
(34)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyHourlyEmployeesPensionPlanMember
Gradall Company Hourly Employees Retirement Plan    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Former employees covered by pension plan 238alg_FormerEmployeesCoveredByPensionPlan
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyEmployeesRetirementPlanMember
 
Current employees covered in the Gradall Company Hourly Employees' Pension Plan who were formerly employed by former parent (Employees) 83alg_CurrentEmployeesCoveredByPensionPlan
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyEmployeesRetirementPlanMember
 
Pension expense $ 11us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyEmployeesRetirementPlanMember
$ (66)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_MultiemployerPlanNameAxis
= alg_GradallCompanyEmployeesRetirementPlanMember