XML 26 R37.htm IDEA: XBRL DOCUMENT v2.4.1.9
Basis of Financial Statement Presentation (Narrative) (Details) (Correction of Misclassification of Freight Revenue, USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Mar. 31, 2014
Correction of Misclassification of Freight Revenue
  
Accounting Policies [Line Items]  
Reclassification of net sales and cost of sales $ 1,359alg_IncreaseDecreaseinRevenueNet
/ us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis
= alg_CorrectionofMisclassificationofFreightRevenueMember