Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2009	$ 55,969,000	$ 32,000	$ 0	$ 173,672,000	$ 0	$ (120,242,000)	$ 2,507,000
Common stock, shares outstanding at Dec. 31, 2009		31,912,066
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Acacia Research Corporation	34,051,000					34,051,000
Stock options exercised, shares		2,852,002
Stock options exercised, value	15,068,000	3,000		15,065,000
Stock issued during period, shares, share-based compensation, net of forfeitures		1,265,000
Compensation expense related to stock options and restricted stock awards	7,121,000	1,000		7,120,000
Excess tax benefits from stock-based compensation	1,302,000			1,302,000
Net income (loss) attributable to noncontrolling interest	2,965,000						2,965,000
Contributions from noncontrolling interests in operating subsidiary, net	2,317,000						2,317,000
Distributions to noncontrolling interests in operating subsidiary	(4,807,000)						(4,807,000)
Adjustments to Additional Paid in Capital, Other	(133,000)			(133,000)
Unrealized gain on foreign currency translation	0
Unrealized gain (loss) on short-term investments	0
Balance at Dec. 31, 2010	113,853,000	36,000	0	197,026,000	0	(86,191,000)	2,982,000
Common stock, shares outstanding at Dec. 31, 2010		36,029,068
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Acacia Research Corporation	21,106,000					21,106,000
Sale of common stock, shares		5,750,000
Sale of common stock, value		6,000		175,223,000
Proceeds from Issuance or Sale of Equity	175,229,000
Stock options exercised, shares		87,068
Stock options exercised, value	411,000			411,000
Stock issued during period, shares, share-based compensation, net of forfeitures		1,061,865
Compensation expense related to stock options and restricted stock awards	13,579,000	1,000		13,578,000
Excess tax benefits from stock-based compensation	583,000			583,000
Net income (loss) attributable to noncontrolling interest	539,000						539,000
Contributions from noncontrolling interests in operating subsidiary, net	1,539,000						1,539,000
Distributions to noncontrolling interests in operating subsidiary	(2,897,000)						(2,897,000)
Unrealized gain on foreign currency translation	0
Unrealized gain (loss) on short-term investments	(1,830,000)
Balance at Dec. 31, 2011	322,112,000	43,000	0	386,821,000	(1,830,000)	(65,085,000)	2,163,000
Common stock, shares outstanding at Dec. 31, 2011	42,928,001	42,928,001
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Acacia Research Corporation	59,453,000
Sale of common stock, shares		6,122,449
Sale of common stock, value	218,961,000	6,000		218,955,000
Treasury stock, shares acquired	1,129,408	(1,129,408)
Treasury stock, cost of shares acquired	(26,732,000)		(26,731,000)
Stock options exercised, shares	71,000	71,272
Stock options exercised, value	340,000			340,000
Stock issued during period, shares, share-based compensation, net of forfeitures		1,168,530
Compensation expense related to stock options and restricted stock awards	25,657,000	1,000		25,656,000
Excess tax benefits from stock-based compensation	13,210,000			13,210,000
Net income (loss) attributable to noncontrolling interest	(164,000)						(164,000)
Contributions from noncontrolling interests in operating subsidiary, net	5,793,000						5,793,000
Distributions to noncontrolling interests in operating subsidiary	(816,000)						(816,000)
Unrealized gain on foreign currency translation	7,000				7,000
Unrealized gain (loss) on short-term investments	657,000				657,000
Balance at Dec. 31, 2012	$ 618,478,000	$ 49,000	$ (26,731,000)	$ 644,982,000	$ (1,166,000)	$ (5,632,000)	$ 6,976,000
Common stock, shares outstanding at Dec. 31, 2012	49,160,844	49,160,844