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Stock-Based Compensation (Narrative) (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation $ 620us-gaap_ShareBasedCompensation $ 575us-gaap_ShareBasedCompensation
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized 4,867us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized  
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 3 years  
Excess Tax Benefit from Share-based Compensation, Financing Activities 310us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities 85us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities
Equity Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period 7,500us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
 
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
 
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
 
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
Restricted Stock And Performance Shares Combined [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation $ 620us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= fstr_RistrictedStockAndPerformanceSharesCombinedMember
$ 575us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= fstr_RistrictedStockAndPerformanceSharesCombinedMember
Weighted Average [Member] | Equity Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price $ 9.08us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
/ us-gaap_RangeAxis
= us-gaap_WeightedAverageMember
 
The Omnibus Plan [Member] | Restricted Stock And Performance Shares Combined [Member] | Vesting Period 1 [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 4 years  
The Omnibus Plan [Member] | Restricted Stock And Performance Shares Combined [Member] | Vesting Period 2 [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 3 years