Summary of Significant Accounting Policies Impact of revision (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Net income (loss) attributable to Acacia Research Corporation	$ (16,244,000)	$ (12,415,000)	$ (12,949,000)	$ (24,421,000)	$ (33,333,000)	$ (15,711,000)	$ (12,503,000)	$ 5,113,000	$ (66,029,000)	$ (56,434,000)	$ 59,453,000
Net Income (Loss) Available to Common Stockholders, Basic									(66,755,000)	(56,945,000)	57,564,000
Net Income (Loss) Available to Common Stockholders, Diluted									(66,755,000)	(56,945,000)	57,577,000
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders – basic - As Reported											47,251,061
Weighted-average number of shares outstanding, basic - As Adjusted(1)	48,944,914	48,806,334	48,543,334	48,329,375	48,415,684	48,330,149	48,008,998	47,859,774	48,658,088	48,155,832	47,251,061
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders – diluted - As Reported											48,060,647
Weighted-average number of shares outstanding, diluted - As Adjusted(1)	48,944,914	48,806,334	48,543,334	48,329,375	48,415,684	48,330,149	48,008,998	48,104,242	48,658,088	48,155,832	47,584,120
Basic net income (loss) per common share, As Reported											1.26
Basic income (loss) per common share	$ (0.34)	$ (0.26)	$ (0.27)	$ (0.51)	$ (0.69)	$ (0.33)	$ (0.26)	$ 0.10	$ (1.37)	$ (1.18)	$ 1.22
Diluted net income (loss) per common share - As Reported											$ 1.24
Diluted income (loss) per common share	$ (0.34)	$ (0.26)	$ (0.27)	$ (0.51)	$ (0.69)	$ (0.33)	$ (0.26)	$ 0.10	$ (1.37)	$ (1.18)	$ 1.21