Note 4 - Loans Leases Receivable - Composition of the Loan Lease Portfolio (Details) - USD ($)		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Loans		$ 2,956,713,493		$ 2,397,414,282
Plus deferred loan/lease origination costs, net of fees		7,771,907		8,072,703
Gross loans/leases receivable		2,964,485,400		2,405,486,985
Less allowance		(34,355,728)		(30,757,448)		$ (26,140,906)	$ (23,074,365)
Net loans/leases receivable	[1]	2,930,129,672		2,374,729,537
Commercial Portfolio Segment [Member]
Loans	[2]	1,134,516,315		827,637,263
Less allowance		(14,323,036)		(12,545,110)		(10,484,080)	(8,833,832)
Commercial Real Estate Portfolio Segment [Member]
Loans		1,303,491,882		1,093,458,860
Less allowance		(13,962,688)		(11,670,609)		(9,375,117)	(8,353,386)
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans		332,742,477		332,387,621
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans		186,402,404		165,149,491
Commercial Real Estate Portfolio Segment [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans		784,347,000		595,921,748
Finance Leases Portfolio Segment [Member]
Loans	[1]	141,448,232		165,419,360
Plus deferred loan/lease origination costs, net of fees	[1]	4,624,027		5,881,778
Gross loans/leases receivable	[1]	146,072,259		171,301,138
Less allowance		(2,382,098)	[1]	(3,111,898)	[1]	(3,395,088)	(3,359,400)
Net loans/leases receivable		143,690,161		168,189,240
Net minimum lease payments to be received	[1]	156,583,887		184,274,802
Estimated unguaranteed residual values of leased assets	[1]	929,932		1,085,154
Unearned lease/residual income	[1]	(16,065,587)		(19,940,596)
Residential Portfolio Segment [Member]
Loans	[3]	258,646,265		229,233,104
Less allowance		(2,466,431)		(2,342,344)		(1,790,150)	(1,525,952)
Consumer Portfolio Segment [Member]
Loans		118,610,799		81,665,695
Less allowance		$ (1,221,475)		$ (1,087,487)		$ (1,096,471)	$ (1,001,795)

[1] 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.

[2] 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.

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