EQUITY SECURITIES PORTFOLIO INVESTMENT - Unrealized and Realized Gains or Losses on Investment (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Change in fair value of investment	$ (172,203)	$ 37,849
Trading Securites - LF Fund Public Securities
Debt and Equity Securities, FV-NI [Line Items]
Change in fair value of investment	(171,640)	5,374
Realized investment gains (losses)	59,488	0
Equity Securities - LF Fund Private Securities
Debt and Equity Securities, FV-NI [Line Items]
Change in fair value of investment	0	31,802
Trading Securites Lf Fund Securities
Debt and Equity Securities, FV-NI [Line Items]
Net realized and unrealized gain (loss) on investments	$ (112,152)	$ 37,176

Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(3)(d))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714

+ Details

Name:	us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of realized and unrealized gain (loss) on investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27405-111563

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(c),9(a))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of realized gain (loss) on investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.3(a))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

+ Details

Name:	us-gaap_RealizedInvestmentGainsLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=actg_TradingSecuritesLfFundPublicSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=actg_EquitySecuritiesLFFundPrivateSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=actg_TradingSecuritesLfFundSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: