Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 08, 2019
Entity Information [Line Items]
Entity Registrant Name	ACACIA RESEARCH CORP
Entity Central Index Key	0000934549
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		49,681,203
Entity Small Business	true
Entity Emerging Growth Company	false