Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
QUARTERLY FINANCIAL DATA (unaudited) [Abstract]
Revenues	$ 21,969	$ 64,658	$ 41,351	$ 24,721	$ 37,497	$ 12,994	$ 40,336	$ 34,210
Inventor royalties	3,313	17,844	0	1,573	7,756	116	1,265	9,325	$ 22,730	$ 18,462	$ 20,670
Contingent legal fees	4,238	7,709	10,418	4,109	3,901	1,972	5,512	4,784	26,474	16,169	23,563
Litigation and licensing expenses - patents	5,463	7,348	7,324	7,723	11,341	10,345	9,012	8,675	27,858	39,373	37,614
Amortization of patents	6,222	6,467	10,759	10,760	13,113	13,688	13,228	13,038	34,208	53,067	53,745
Marketing, general and administrative expenses (including non-cash stock compensation expense)	(9,056)	(8,334)	(7,535)	(7,994)	(8,572)	(9,442)	(9,587)	(10,575)	(32,919)	(38,176)	(48,554)
Research, consulting and other expenses - business development	557	666	1,334	522	860	802	732	997	3,079	3,391	3,840
Impairment of Patent-Related Intangible Assets	2,175	0	40,165	0	74,731	0	0	0	42,340	74,731	3,497
Impairment of Goodwill	0	0	0	0	30,149	0	0	0	0	30,149	0
Other	0	0	(1,242)	1,742	250	3,465	0	426	500	4,141	1,548
Total operating costs and expenses	31,024	48,368	76,293	34,423	150,673	39,830	39,336	47,820	190,108	277,659	193,031
Operating loss	(9,055)	16,290	(34,942)	(9,702)	(113,176)	(26,836)	1,000	(13,610)	(37,409)	(152,622)	(62,155)
Total other income (expense)	592	261	(52)	(3)	0	(180)	(104)	228	798	(56)	(595)
Income (loss) from operations before (provision for) benefit from income taxes	(8,463)	16,551	(34,994)	(9,705)	(113,176)	(27,016)	896	(13,382)	(36,611)	(152,678)	(62,750)
(Provision) benefit for income taxes	(2,414)	(9,655)	(5,927)	(192)	(4,174)	(337)	(119)	(170)	(18,188)	(4,800)	(3,912)
Net loss including noncontrolling interests in operating subsidiaries	(10,877)	6,896	(40,921)	(9,897)	(117,350)	(27,353)	777	(13,552)	(54,799)	(157,478)	(66,662)
Net (income) loss attributable to noncontrolling interests in operating subsidiaries	(266)	(186)	(348)	68	(1,440)	(43)	4,463	(422)	(732)	2,558	(633)
Net loss attributable to Acacia Research Corporation	$ (10,611)	$ 7,082	$ (40,573)	$ (9,965)	$ (115,910)	$ (27,310)	$ (3,686)	$ (13,130)	$ (54,067)	$ (160,036)	$ (66,029)
Earnings Per Share, Basic and Diluted	$ (0.21)	$ 0.14	$ (0.81)	$ (0.20)	$ (2.33)	$ (0.55)	$ (0.08)	$ (0.27)	$ (1.08)	$ (3.25)	$ (1.37)
Weighted Average Number of Shares Outstanding, Basic and Diluted	50,237,784	50,124,302	50,015,869	49,925,550	49,749,941	49,630,369	49,423,472	49,212,207	50,075,847	49,505,817	48,658,088
Weighted Average Number of Shares Outstanding, Diluted	50,237,784	50,618,757	50,015,869	49,925,550	49,749,941	49,630,369	49,423,472	49,212,207