Acquisition Pro Forma Information (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Business Combinations [Abstract]
Pro forma revenues	$ 250,727
Pro forma total operating costs and expenses	170,953
Pro forma operating income	79,774
Pro forma interest and investment income	937
Pro forma income from operations before provision for income taxes	80,711
Pro forma provision for income taxes	(22,060)
Pro forma net income including noncontrolling interests	58,651
Pro forma net (income) loss attributable to noncontrolling interests	164
Pro forma net income attributable to Acacia Research Corporation	$ 58,815
Pro forma income per common share attributable to Acacia Research Corporation [Abstract]
Pro forma basic earnings per share	$ 1.24
Pro forma diluted earnings per share	$ 1.22
Pro forma weighted average number of shares outstanding, basic	47,251,061
Pro forma weighted average number of shares outstanding, diluted	48,060,647

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

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