Note 4 - Loans Leases Receivable - Loans Leases Nonperforming Loans Leases (Details) - USD ($)		Dec. 31, 2017	Sep. 30, 2017		Dec. 31, 2016
Accruing Past Due 90 Days or More		$ 88,671			$ 966,814
Nonaccrual Loans/Leases		11,441,234			13,919,066
Accruing TDRs		9,394,967			8,647,007
Loans		$ 2,956,713,493			$ 2,397,414,282
Percentage of Total NPLs		100.00%			100.00%
Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More			$ 88,671		$ 966,814
Nonaccrual Loans/Leases			11,441,234	[1]	13,919,066	[2]
Accruing TDRs			7,112,472		6,346,528
Loans			$ 18,642,377		$ 21,232,408
Percentage of Total NPLs			100.00%		100.00%
Commercial Portfolio Segment [Member]
Accruing Past Due 90 Days or More					$ 346,234
Nonaccrual Loans/Leases		1,231,353			4,187,786	[2]
Loans	[3]	1,134,516,315			827,637,263
Commercial Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases	[1]		1,231,353
Accruing TDRs			5,224,182		4,733,997
Loans			$ 6,455,535		$ 9,268,017
Percentage of Total NPLs			34.63%		43.65%
Commercial Real Estate Portfolio Segment [Member]
Loans		1,303,491,882			$ 1,093,458,860
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases		333,900			332,148	[2]
Loans		332,742,477			332,387,621
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases		4,844,312			4,353,819	[2]
Loans		186,402,404			165,149,491
Commercial Real Estate Portfolio Segment [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases		1,243,728			1,436,149	[2]
Loans		784,347,000			595,921,748
Commercial Real Estate Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases	[1]		333,900
Accruing TDRs			107,322
Loans			$ 441,222		$ 332,148
Percentage of Total NPLs			2.37%		1.56%
Commercial Real Estate Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Construction Loans [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases	[1]		4,844,312
Accruing TDRs
Loans			$ 4,844,312		$ 4,353,819
Percentage of Total NPLs			25.99%		20.51%
Commercial Real Estate Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases	[1]		1,243,728
Accruing TDRs
Loans			$ 1,243,728		$ 1,436,149
Percentage of Total NPLs			6.67%		6.77%
Finance Leases Portfolio Segment [Member]
Accruing Past Due 90 Days or More					$ 215,225
Nonaccrual Loans/Leases		2,175,044			2,446,181	[2]
Loans	[4]	141,448,232			165,419,360
Finance Leases Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More
Nonaccrual Loans/Leases	[1]		2,175,044
Accruing TDRs			1,494,448		1,008,244
Loans		3,669,492	$ 3,669,492		$ 3,669,650
Percentage of Total NPLs			19.68%		17.28%
Residential Portfolio Segment [Member]
Accruing Past Due 90 Days or More		74,519			$ 294,854
Nonaccrual Loans/Leases		1,363,806			1,075,639	[2]
Loans	[5]	258,646,265			229,233,104
Residential Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More			$ 74,519
Nonaccrual Loans/Leases	[1]		1,363,806
Accruing TDRs			272,493		585,541
Loans		1,710,818	$ 1,710,818		$ 1,956,034
Percentage of Total NPLs			9.18%		9.21%
Consumer Portfolio Segment [Member]
Accruing Past Due 90 Days or More		14,152			$ 110,501
Nonaccrual Loans/Leases		249,091			87,344	[2]
Loans		118,610,799			81,665,695
Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More			$ 14,152
Nonaccrual Loans/Leases	[1]		249,091
Accruing TDRs			14,027		18,746
Loans		$ 277,270	$ 277,270		$ 216,591
Percentage of Total NPLs			1.49%		1.02%

[1] At December 31, 2017, nonaccrual loans/leases included $2,282,495 of TDRs, including $122,598 in C&I loans, $1,336,871 in CRE loans, $700,255 in direct financing leases, $115,190 in residential real estate loans, and $7,581 in installment loans.

[2] At December 31, 2016, 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.

[3] 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.

[4] 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.

[5] Includes residential real estate loans held for sale totaling $645,001 and $1,135,500 as of December 31, 2017 and 2016, respectively.