Note 3 - Loans Leases Receivable (Details Textual)		3 Months Ended					9 Months Ended		12 Months Ended
		Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)		Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Losses on Residual Value		$ 0				$ 0	$ 0	$ 0
Loans and Leases Receivable, Net of Deferred Income		2,669,013,113		$ 2,397,414,282			2,669,013,113		$ 2,397,414,282
Financing Receivable, Recorded Investment, Nonaccrual Status		20,443,137		13,919,066			20,443,137		13,919,066
Financing Receivable, Modifications, Recorded Investment		$ 9,854,487		8,647,007			$ 9,854,487		8,647,007
Financing Receivable, Modifications, Number of Contracts		8				2	36	13
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 1,037,049				$ 461,643	$ 2,795,032	$ 2,530,491
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down			$ 112,000	$ 195,000					236,545
Financing Receivable, Modifications, Subsequent Default, Number of Contracts		4	2	2		0	4	0
Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts							3	2
Financing Receivable, Modifications, Post-Modification Recorded Investment							$ 139,241	$ 1,384,680
Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 2,291,666		$ 2,300,479			2,291,666		$ 2,300,479
Financing Receivable, Modifications, Number of Contracts									1
Residential Portfolio Segment [Member]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage		290,320		1,135,500			290,320		$ 1,135,500
Loans and Leases Receivable, Net of Deferred Income	[1],[2]	239,957,916		229,233,104			239,957,916		229,233,104
Financing Receivable, Recorded Investment, Nonaccrual Status		917,857		1,075,639	[3]		917,857		1,075,639	[3]
Residential Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		40,405		43,579			40,405		43,579
Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income	[4]	1,034,530,786		827,637,263			1,034,530,786		827,637,263
Financing Receivable, Recorded Investment, Nonaccrual Status		1,567,813		4,187,786	[3]		1,567,813		4,187,786	[3]
Commercial Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		258,598		48,501			258,598		48,501
Commercial Portfolio Segment [Member] | m2 Lease Funds, LLC [Member]
Loans and Leases Receivable, Net of Deferred Income		60,981,381		38,668,209			60,981,381		38,668,209
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income		1,157,855,663		1,093,458,860			1,157,855,663		1,093,458,860
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans and Leases Receivable, Net of Deferred Income		168,992,704		165,149,491			168,992,704		165,149,491
Financing Receivable, Recorded Investment, Nonaccrual Status		4,344,742		4,353,819	[3]		4,344,742		4,353,819	[3]
Commercial Real Estate Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		1,198,439		1,380,047			1,198,439		1,380,047
Commercial Real Estate Portfolio Segment [Member] | Troubled Debt Restructurings [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		177,606					177,606
Finance Leases Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income	[2],[5]	147,062,893		165,419,360			147,062,893		165,419,360
Financing Receivable, Recorded Investment, Nonaccrual Status		2,238,372		2,446,181	[3]		2,238,372		2,446,181	[3]
Finance Leases Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		607,882		816,149			607,882		816,149
Consumer Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income	[2]	89,605,855		81,665,695			89,605,855		81,665,695
Financing Receivable, Recorded Investment, Nonaccrual Status		237,488		87,344	[3]		237,488		87,344	[3]
Consumer Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 8,736		$ 12,203			$ 8,736		$ 12,203

[1] Includes residential real estate loans held for sale totaling $290,320 and $1,135,500 as of September 30, 2017, and December 31, 2016, respectively.

[2] Performing = loans/leases accruing and less than 90 days past due. Nonperforming = loans/leases on nonaccrual, accruing loans/leases that are greater than or equal to 90 days past due, and accruing TDRs.

[3] Nonaccrual loans/leases included $2,300,479 of TDRs, including $48,501 in C&I loans, $1,380,047 in CRE loans, $816,149 in direct financing leases, $43,579 in residential real estate loans, and $12,203 in installment loans.

[4] Includes loans outstanding at QCBT's wholly-owned subsidiary, m2, totaling $60,981,381 and $38,668,209 as of September 30, 2017 and December 31, 2016, respectively.

[5] Management performs an evaluation of the estimated unguaranteed residual values of leased assets on an annual basis, at a minimum. The evaluation consists of discussions with reputable and current vendors, which is combined with management's expertise and understanding of the current states of particular industries to determine informal valuations of the equipment. As necessary and where available, management will utilize valuations by independent appraisers. The large majority of leases with residual values contain a lease options rider, which requires the lessee to pay the residual value directly, finance the payment of the residual value, or extend the lease term to pay the residual value. In these cases, the residual value is protected and the risk of loss is minimal. There were no losses related to residual values for the three and nine months ended September 30, 2017 and 2016.