Note 7 - Derivatives and Hedging Activities - Summary of Interest Rate Swaps Derivatives (Details)	12 Months Ended
	Dec. 31, 2018 USD ($)
Interest rate swap
Notional Amount	$ 39,000,000
Fair Value - Liability	$ 1,151,174
Receive Rate	4.94%
Pay Rate	5.24%
Designated as Hedging Instrument [Member] | Other Liabilities. | Cash Flow Hedging [Member] | QCR Holdings Statutory Trust II
Notional Amount	$ 10,000,000
Fair Value - Liability	$ 298,367
Receive Rate	5.65%
Pay Rate	5.85%
Designated as Hedging Instrument [Member] | Other Liabilities. | Cash Flow Hedging [Member] | QCR Holdings Statutory Trust III
Notional Amount	$ 8,000,000
Fair Value - Liability	$ 238,693
Receive Rate	5.65%
Pay Rate	5.85%
Designated as Hedging Instrument [Member] | Other Liabilities. | Cash Flow Hedging [Member] | QCR Holdings Statutory Trust V
Notional Amount	$ 10,000,000
Fair Value - Liability	$ 287,716
Receive Rate	3.99%
Pay Rate	4.54%
Designated as Hedging Instrument [Member] | Other Liabilities. | Cash Flow Hedging [Member] | Community National Statutory Trust II
Notional Amount	$ 3,000,000
Fair Value - Liability	$ 89,008
Receive Rate	4.96%
Pay Rate	5.17%
Designated as Hedging Instrument [Member] | Other Liabilities. | Cash Flow Hedging [Member] | Community National Statutory Trust III
Notional Amount	$ 3,500,000
Fair Value - Liability	$ 103,858
Receive Rate	4.54%
Pay Rate	4.75%
Designated as Hedging Instrument [Member] | Other Liabilities. | Cash Flow Hedging [Member] | Guaranty Bankshares Statutory Trust I
Notional Amount	$ 4,500,000
Fair Value - Liability	$ 133,532
Receive Rate	4.54%
Pay Rate	4.75%