Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Narrative) (Details)

v2.4.1.9
Stock-Based Compensation (Narrative) (Details) (USD $)
3 Months Ended 1 Months Ended 0 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Apr. 30, 2015
Apr. 03, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of options outstanding 635,250us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber       540,404us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Aggregate intrinsic value of options outstanding $ 158,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue        
Intrinsic value of all options exercised 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue        
Net cash proceeds from exercise of stock options 0us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions 0us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions      
Unrecognized compensation expense for awards 1,204,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions        
Recognition period for unrecognized compensation expense 2 years 8 months 12 days        
Excess tax benefits from exercise of stock options (6,000)us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions (9,000)us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions      
Share based compensation expense before income taxes 238,000us-gaap_AllocatedShareBasedCompensationExpense 48,000us-gaap_AllocatedShareBasedCompensationExpense      
Share based compensation expense after income taxes $ 155,000us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax $ 31,000us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax      
Employee Stock Purchase Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Percentage of price of common stock at which employees are able to acquire 85.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
       
Shares available 17,455us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
       
Employee Stock Purchase Plan [Member] | Subsequent Event [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of additional awards authorized     100,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
   
Number of awards authorized     600,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
   
2011 Executive Incentive Compensation Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of awards authorized 1,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
       
Award vesting percentage 25.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
       
Awards eligible for grant 133,056us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
       
Shares issued under Plan 65,651us-gaap_SharesIssued
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
       
Number of options outstanding 801,293us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
       
2011 Executive Incentive Compensation Plan [Member] | Subsequent Event [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of additional awards authorized       1,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
 
Number of awards authorized       2,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
 
Stock Option Plan For Directors [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of options granted 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_PlanNameAxis
= jcs_StockOptionPlanForDirectorsMember
      0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_PlanNameAxis
= jcs_StockOptionPlanForDirectorsMember
Award expiration period 10 years        
1992 Stock Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares available 22,008us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
/ us-gaap_PlanNameAxis
= jcs_NineteenNinetyTwoStockPlanMember
       
Number of options granted 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_PlanNameAxis
= jcs_NineteenNinetyTwoStockPlanMember
       
Deferred stock awards granted 0us-gaap_DeferredCompensationArrangementWithIndividualSharesIssued
/ us-gaap_PlanNameAxis
= jcs_NineteenNinetyTwoStockPlanMember
       
Key Employees [Member] | 2011 Executive Incentive Compensation Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Deferred stock awards granted 100,017us-gaap_DeferredCompensationArrangementWithIndividualSharesIssued
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
/ us-gaap_TitleOfIndividualAxis
= jcs_KeyEmployeesMember
       
Key Executive Employees [Member] | 2011 Executive Incentive Compensation Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of options granted 105,279us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_PlanNameAxis
= jcs_TwoThousandElevenExecutiveIncentiveCompensationPlanMember
/ us-gaap_TitleOfIndividualAxis
= jcs_KeyExecutiveEmployeesMember
       
Award expiration period 7 years        
Deferred Stock [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Awards granted 100,017us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember