Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation (Details Textual)

v2.4.1.9
Stock Based Compensation (Details Textual) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares of common stock authorized under stock compensation plan 10,050,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized    
Remaining shares available for grant 1,629,767us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant    
Total intrinsic value of options exercises $ 1.7us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue $ 4.8us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue $ 5.4us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Performance based awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period for non-vested stock awards and stock options 3 years    
Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period for non-vested stock awards and stock options 3 years    
Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period for non-vested stock awards and stock options 5 years