Quarterly report pursuant to Section 13 or 15(d)

Supplemental Retirement Plan and Related Post Retirement Benefits - Summarizes the Components of Net Periodic Cost (Detail)

v2.4.1.9
Supplemental Retirement Plan and Related Post Retirement Benefits - Summarizes the Components of Net Periodic Cost (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Apr. 04, 2015
Mar. 29, 2014
SERP [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Service cost $ 48us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
$ 62us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Interest cost 211us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
188us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Amortization of prior service cost 124us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
130us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Amortization of net actuarial losses 112us-gaap_DefinedBenefitPlanFutureAmortizationOfGainLoss
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
27us-gaap_DefinedBenefitPlanFutureAmortizationOfGainLoss
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Net periodic cost 495us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
407us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
SERP Medical [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 2us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
1us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
Interest cost 10us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
8us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
Amortization of prior service cost 6us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
6us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
Amortization of net actuarial losses 6us-gaap_DefinedBenefitPlanFutureAmortizationOfGainLoss
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
 
Net periodic cost $ 24us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember
$ 15us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= atro_SupplementalEmployeeRetirementPlanDefinedBenefitMedicalMember