Note 7 - Derivatives and Hedging Activities - Summary of Interest Rate Swaps Derivatives (Details) - Designated as Hedging Instrument [Member] - Other Liabilities. - Cash Flow Hedging [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Interest rate swap
Notional Amount	$ 39,000
Fair Value - Liability	$ (3,758)	$ (1,151)
Receive Rate	4.18%
Pay Rate	5.24%
QCR Holdings Statutory Trust II
Notional Amount	$ 10,000
Fair Value - Liability	$ (971)	(298)
Receive Rate	4.79%
Pay Rate	5.85%
QCR Holdings Statutory Trust III
Notional Amount	$ 8,000
Fair Value - Liability	$ (777)	(239)
Receive Rate	4.79%
Pay Rate	5.85%
QCR Holdings Statutory Trust V
Notional Amount	$ 10,000
Fair Value - Liability	$ (944)	(288)
Receive Rate	3.54%
Pay Rate	4.54%
Community National Statutory Trust II
Notional Amount	$ 3,000
Fair Value - Liability	$ (291)	(89)
Receive Rate	4.08%
Pay Rate	5.17%
Community National Statutory Trust III
Notional Amount	$ 3,500
Fair Value - Liability	$ (339)	(104)
Receive Rate	3.64%
Pay Rate	4.75%
Guaranty Bankshares Statutory Trust I
Notional Amount	$ 4,500
Fair Value - Liability	$ (436)	$ (133)
Receive Rate	3.64%
Pay Rate	4.75%