Summary of Significant Accounting Policies Impact of revision (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounting Policies [Abstract]
Net Income (Loss) Attributable to Acacia Research Corporation	$ (33,333,000)	$ (15,711,000)	$ (12,503,000)	$ 5,113,000	$ 9,823,000	$ (6,619,000)	$ 6,321,000	$ 49,928,000	$ (56,434,000)	$ 59,453,000	$ 21,106,000
Net Income (Loss) Available to Common Stockholders, Basic									(56,945,000)	57,564,000	20,265,000
Net Income (Loss) Available to Common Stockholders, Diluted									(56,945,000)	57,577,000	20,273,000
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders – basic - As Reported										47,251,061	39,743,433
Weighted-average number of shares outstanding, basic - As Adjusted(1)	48,415,684	48,330,149	48,008,998	47,859,774	48,335,865	48,332,878	47,944,193	44,367,499	48,155,832	47,251,061	39,743,433
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders – diluted - As Reported										48,060,647	41,258,297
Weighted-average number of shares outstanding, diluted - As Adjusted(1)	48,415,684	48,330,149	48,008,998	48,104,242	48,607,141	48,332,878	48,294,782	44,764,064	48,155,832	47,584,120	40,150,600
Basic net income (loss) per common share, As Reported										1.26	0.53
Basic income (loss) per common share	$ (0.69)	$ (0.33)	$ (0.26)	$ 0.10	$ 0.20	$ (0.14)	$ 0.13	$ 1.08	$ (1.18)	$ 1.22	$ 0.51
Diluted net income (loss) per common share - As Reported										$ 1.24	$ 0.51
Diluted income (loss) per common share	$ (0.69)	$ (0.33)	$ (0.26)	$ 0.10	$ 0.20	$ (0.14)	$ 0.13	$ 1.08	$ (1.18)	$ 1.21	$ 0.50