Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2014	$ 489,048	$ 50	$ (34,640)	$ 646,595	$ (353)	$ (128,095)	$ 5,491
Common stock, shares outstanding at Dec. 31, 2014		50,065,382
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Acacia Research Corporation	(160,036)					(160,036)
Payments of Dividends	(25,434)			(25,434)
Stock options exercised, shares		135,000
Proceeds from Stock Options Exercised	938
Stock options exercised, value	938			938
Stock issued during period, shares, share-based compensation, net of forfeitures		450,857
Non-cash stock compensation	11,048	$ 1		11,047
Net (income) loss attributable to noncontrolling interests in subsidiaries	2,558						2,558
Payments to Noncontrolling Interests	4,105
Foreign Currency Transaction Gain (Loss), Unrealized	(123)				(123)
Unrealized Gain (Loss) on Investments	261				261
Distributions to noncontrolling interests in operating subsidiary	(4,105)						(4,105)
Payments for Repurchase of Common Stock	0
Balance at Dec. 31, 2015	314,155	$ 51	(34,640)	633,146	(215)	(288,131)	3,944
Common stock, shares outstanding at Dec. 31, 2015		50,651,239
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Acacia Research Corporation	(54,067)					(54,067)
Payments of Dividends	$ 0
Stock Repurchased During Period, Shares	(13,529)
Stock options exercised, shares		100,992
Proceeds from Stock Options Exercised	$ 326
Stock options exercised, value				326
Stock issued during period, shares, share-based compensation, net of forfeitures		(262,660)
Non-cash stock compensation	9,062	$ (1)		9,063
Net (income) loss attributable to noncontrolling interests in subsidiaries	(732)						(732)
Payments to Noncontrolling Interests	1,358						(1,358)
Foreign Currency Transaction Gain (Loss), Unrealized					99
Unrealized Gain (Loss) on Investments					40
Distributions to noncontrolling interests in operating subsidiary							(1,358)
Payments for Repurchase of Common Stock	(82)
Balance at Dec. 31, 2016	$ 267,443	$ 50	(34,640)	642,453	(76)	(342,198)	1,854
Common stock, shares outstanding at Dec. 31, 2016	50,476,042	50,476,042
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Acacia Research Corporation	$ 22,180					22,180
Payments of Dividends	$ 0
Stock Repurchased During Period, Shares	(8,669)
Stock options exercised, shares	208,000	207,863
Proceeds from Stock Options Exercised	$ 745	$ 1		744
Stock options exercised, value				745
Stock issued during period, shares, share-based compensation, net of forfeitures		(35,310)
Non-cash stock compensation	8,885	$ 0
General and administrative expenses excluding share-based compensation				5,844
Net (income) loss attributable to noncontrolling interests in subsidiaries	(496)						(496)
Payments to Noncontrolling Interests	0
Foreign Currency Transaction Gain (Loss), Unrealized					28
Unrealized Gain (Loss) on Investments					(40)
Payments for Repurchase of Common Stock	(45)
Balance at Dec. 31, 2017	$ 295,659	$ 51	$ (34,640)	$ 648,996	$ (88)	$ (320,018)	$ 1,358
Common stock, shares outstanding at Dec. 31, 2017	50,639,926	50,639,926