Summary of Significant Accounting Policies Earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Net income (loss) attributable to Acacia Research Corporation	$ (115,910)	$ (27,310)	$ (3,686)	$ (13,130)	$ (16,244)	$ (12,415)	$ (12,949)	$ (24,421)	$ (160,036)	$ (66,029)	$ (56,434)
Payments of Dividends									(25,434)	(25,039)	(18,633)
Dividends attributable to common stockholders under the two class method									24,740	24,313	18,122
Net Loss Available to Common Stockholders, Basic and Diluted									$ (160,730)	$ (66,755)	$ (56,945)
Weighted Average Number of Shares Outstanding, Basic and Diluted	49,749,941	49,630,369	49,423,472	49,212,207	48,944,914	48,806,334	48,543,334	48,329,375	49,505,817	48,658,088	48,155,832
Earnings Per Share, Basic and Diluted	$ (2.33)	$ (0.55)	$ (0.08)	$ (0.27)	$ (0.34)	$ (0.26)	$ (0.27)	$ (0.51)	$ (3.25)	$ (1.37)	$ (1.18)
Anti-dilutive equity-based incentive awards excluded from the computation of diluted income (loss) per share									71,468	27,760	27,760