v2.4.1.9
OTHER INVESTMENTS (Narrative) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2007
Dec. 31, 2008
Dec. 31, 2010
Sep. 30, 2012
Dec. 31, 2011
Apr. 30, 2011
Mar. 31, 2011
Feb. 28, 2010
Schedule of Equity Method Investments [Line Items]                      
Number of unlisted entities 5acts_EquityMethodInvestmentNumberOfUnlistedEntities                    
Impairment charges    $ 681us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet $ 2,543us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet                
Write down of investments   819us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment                  
Carrying value 27,352us-gaap_EquityMethodInvestments 17,843us-gaap_EquityMethodInvestments                  
AMC [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Ownership percentage       5.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_AMCHoldingLimitedMember
             
Capital investment       27,000us-gaap_EquityMethodInvestmentAggregateCost
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_AMCHoldingLimitedMember
             
Carrying value                        
Actar [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Ownership percentage         7.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_ActarLimitedMember
           
Capital investment         3,000us-gaap_EquityMethodInvestmentAggregateCost
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_ActarLimitedMember
           
Carrying value                        
Hi-Trend [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Ownership percentage           10.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_HiTrendInvestmentHoldingsCoLtdMember
         
Capital investment           800us-gaap_EquityMethodInvestmentAggregateCost
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_HiTrendInvestmentHoldingsCoLtdMember
         
Carrying value 1,081us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_HiTrendInvestmentHoldingsCoLtdMember
1,102us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_HiTrendInvestmentHoldingsCoLtdMember
                 
Additional capital           202us-gaap_AdditionalPaidInCapital
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_HiTrendInvestmentHoldingsCoLtdMember
         
Dilution of ownership percentage           9.00%acts_EquityMethodInvestmentDilutionOfOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_HiTrendInvestmentHoldingsCoLtdMember
         
Grand Choice [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Ownership percentage     19.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
      12.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
      20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
Capital investment     1,500us-gaap_EquityMethodInvestmentAggregateCost
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
              600us-gaap_EquityMethodInvestmentAggregateCost
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
Carrying value 819us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
819us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
          804us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
     
Additional capital           600us-gaap_AdditionalPaidInCapital
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
    10,000us-gaap_AdditionalPaidInCapital
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
7,986us-gaap_AdditionalPaidInCapital
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
 
Dilution of ownership percentage                 12.00%acts_EquityMethodInvestmentDilutionOfOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
15.00%acts_EquityMethodInvestmentDilutionOfOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_GrandChoiceInvestmentLimitedMember
 
OCTT [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Ownership percentage               19.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_OCTTAsiaLimitedMember
     
Capital investment               13,727us-gaap_EquityMethodInvestmentAggregateCost
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_OCTTAsiaLimitedMember
     
Carrying value 13,727us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_OCTTAsiaLimitedMember
13,727us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_OCTTAsiaLimitedMember
                 
Investees One [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Impairment charges     803us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_PrivateEntityInvesteesOneMember
               
Write down of investments     1,500us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_PrivateEntityInvesteesOneMember
               
Investees Two [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Impairment charges     1,740us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= acts_PrivateEntitiesInvesteesTwoMember
               
Write down of investments