v2.4.1.9

FAIR VALUE MEASUREMENTS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 70us-gaap_TradingSecurities	$ 74us-gaap_TradingSecurities
Publicly traded mutual funds in Taiwan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	70us-gaap_TradingSecurities / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = acts_PubliclyTradedMutualFundsTradingSecuritiesMember	74us-gaap_TradingSecurities / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = acts_PubliclyTradedMutualFundsTradingSecuritiesMember
Quoted prices in active markets for identical instruments (level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	70us-gaap_TradingSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	74us-gaap_TradingSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted prices in active markets for identical instruments (level 1) [Member] | Publicly traded mutual funds in Taiwan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	70us-gaap_TradingSecurities / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = acts_PubliclyTradedMutualFundsTradingSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	74us-gaap_TradingSecurities / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = acts_PubliclyTradedMutualFundsTradingSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Significant other observable inputs (level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities
Significant other observable inputs (level 2) [Member] | Publicly traded mutual funds in Taiwan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities
Significant unobservable inputs (level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities
Significant unobservable inputs (level 3) [Member] | Publicly traded mutual funds in Taiwan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities

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- Definition

Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.4)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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