Note 4 - Borrowings (Details Textual) - USD ($)		1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2016	Jun. 30, 2016	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate		2.50%					2.50%
Revolving Credit Facility [Member]
Long-term Line of Credit							$ 0
Line of Credit Facility, Maximum Borrowing Capacity		$ 10,000,000	$ 10,000,000		$ 10,000,000		$ 40,000,000
Debt Instrument, Interest Rate, Effective Percentage			3.34%		3.34%		3.10%
Proceeds from Lines of Credit	$ 5,000,000				$ 5,000,000
Whole sale Repurchase Agreements [Member]
Repayments of Other Debt			$ 55,000,000	$ 10,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Two			10,000,000		10,000,000		$ 10,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three							10,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four			10,000,000		10,000,000		45,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five			25,000,000		25,000,000		45,000,000
Securities Sold under Agreements to Repurchase, Fair Value of Collateral			27,800,000		27,800,000
Long-term Debt			$ 45,000,000		$ 45,000,000		$ 110,000,000
Wholesale Repurchase Agreement and FHLB Advances [Member]
Debt Instrument, Interest Rate, Stated Percentage			3.24%	3.92%	3.24%
Gain (Loss) on Extinguishment of Debt			$ 4,100,000	$ (1,300,000)
Extinguished Debt Weighted Average Term			2 years 346 days	2 years 62 days
Long-term Debt, Maturities, Repayments of Principal in Year Two				$ 10,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three			$ 5,000,000	$ 10,000,000	$ 5,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four			35,000,000		35,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five			20,000,000		20,000,000
Revolving Line of Credit Note [Member]
Long-term Debt			35,000,000		35,000,000
London Interbank Offered Rate (LIBOR) [Member] | Junior Subordinated Debt [Member]
Debt Instrument, Basis Spread on Variable Rate				1.80%
Term Note [Member]
Long-term Debt, Maturities, Repayments of Principal in Year Two			6,000,000		6,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three			6,000,000		6,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four			6,000,000		6,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five			$ 6,000,000		$ 6,000,000
Debt Instrument, Basis Spread on Variable Rate		3.00%
Debt Instrument, Interest Rate, Effective Percentage			3.84%		3.84%
Notes Payable		$ 30,000,000
Debt Instrument, Term		5 years
Proceeds from Notes Payable	$ 30,000,000
Long-term Debt			$ 30,000,000		$ 30,000,000
Debt Instrument, Periodic Payment, Principal					1,500,000
Junior Subordinated Debt [Member] | Note Payable to QCR Holdings Capital Trust IV [Member]
Gain (Loss) on Extinguishment of Debt				$ 1,200,000
Debt Instrument, Interest Rate, Effective Percentage				2.42%
Extinguishment of Debt, Amount				$ 5,100,000
Repayments of Other Debt					50,320,407	$ 29,177,000
Repayments of Federal Home Loan Bank Borrowings			$ 5,000,000	$ 10,000,000	$ 10,524,197	$ 81,192,185
Short-term Debt, Weighted Average Interest Rate			0.50%	0.50%	0.50%
Notes Payable			$ 30,000,000		$ 30,000,000