Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 01, 2021
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2021
Entity File Number	0-22208
Entity Registrant Name	QCR HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	42-1397595
Entity Address, Address Line One	3551 7th Street
Entity Address, City or Town	Moline
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	61265
City Area Code	309
Local Phone Number	736-3580
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $1.00 Par Value
Trading Symbol	QCRH
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding (in shares)		15,769,161
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Central Index Key	0000906465
Amendment Flag	false