Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Revenues	$ 130,876	$ 130,556	$ 250,727
Cost of revenues:
Inventor royalties	20,670	29,724	26,028
Contingent legal fees	23,563	24,784	24,651
Litigation and licensing expenses - patents	37,614	39,335	21,591
Amortization of patents	57,242	53,658	39,019
Marketing, general and administrative expenses (including non-cash stock compensation expense of $18,115 in 2014, $27,894 in 2013 and $25,657 in 2012)	48,554	59,229	54,083
Research, consulting and other expenses - business development	3,840	3,251	4,943
Other	1,548	3,506	0
Total operating costs and expenses	193,031	213,487	170,315
Operating income (loss)	(62,155)	(82,931)	80,412
Other income	0	0	500
Interest and other investment income (loss)	(595)	2,131	482
Write off of investment	0	0	(45)
Total other income (expense)	(595)	2,131	937
Income (loss) from operations before (provision for) benefit from income taxes	(62,750)	(80,800)	81,349
(Provision for) benefit from income taxes	(3,912)	21,958	(22,060)
Net income (loss) including noncontrolling interests in operating subsidiaries	(66,662)	(58,842)	59,289
Net loss attributable to noncontrolling interests in operating subsidiaries	633	2,408	164
Net income (loss) attributable to Acacia Research Corporation	(66,029)	(56,434)	59,453
Net Income (Loss) Available to Common Stockholders, Basic	(66,755)	(56,945)	57,564
Net Income (Loss) Available to Common Stockholders, Diluted	$ (66,755)	$ (56,945)	$ 57,577
Basic income (loss) per common share	$ (1.37)	$ (1.18)	$ 1.22
Diluted income (loss) per common share	$ (1.37)	$ (1.18)	$ 1.21
Weighted-average number of shares outstanding, basic	48,658,088	48,155,832	47,251,061
Weighted-average number of shares outstanding, diluted	48,658,088	48,155,832	47,584,120
Common Stock, Dividends, Per Share, Cash Paid	$ 0.500	$ 0.375	$ 0.000