Summary of Significant Accounting Policies Earnings per share (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
Accounting Policies [Abstract]
Net income (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)
Payments of Dividends									0	(25,434)	(25,039)
Dividends attributable to common stockholders under the two class method									0	24,740	24,313
Net Loss Available to Common Stockholders, Basic and Diluted									$ (54,067)	$ (160,730)	$ (66,755)
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
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)
Anti-dilutive equity-based incentive awards excluded from the computation of diluted income (loss) per share									3,682,532	71,468	27,760