Note 4 - Derivatives and Hedging Activities - Summary of Interest Rate Swaps Derivatives (Details) - Other Liabilities. - Cash Flow Hedging [Member]	6 Months Ended
	Jun. 30, 2018 USD ($)
National Amount	$ 39,000,000
Fair value	$ 372,050
Receive Rate	4.58%
Pay Rate	5.24%
QCR Holdings Statutory Trust II
National Amount	$ 10,000,000
Fair value	$ 94,210
Receive Rate	5.19%
Pay Rate	5.85%
QCR Holdings Statutory Trust III
National Amount	$ 8,000,000
Fair value	$ 75,368
Receive Rate	5.19%
Pay Rate	5.85%
QCR Holdings Statutory Trust V
National Amount	$ 10,000,000
Fair value	$ 97,961
Receive Rate	3.90%
Pay Rate	4.54%
Community National Statutory Trust II
National Amount	$ 3,000,000
Fair value	$ 28,329
Receive Rate	4.49%
Pay Rate	5.17%
Community National Statutory Trust III
National Amount	$ 3,500,000
Fair value	$ 33,330
Receive Rate	4.09%
Pay Rate	4.75%
Guaranty Bankshares Statutory Trust I
National Amount	$ 4,500,000
Fair value	$ 42,852
Receive Rate	4.09%
Pay Rate	4.75%