Note 3 - Loans Leases Receivable - Loans by Internally Assigned Risk Rating (Details) - USD ($)		Sep. 30, 2017	Dec. 31, 2016
Loans		$ 2,669,013,113	$ 2,397,414,282
Commercial Portfolio Segment [Member]
Loans	[1]	1,034,530,786	827,637,263
Commercial Portfolio Segment [Member] | Pass [Member]
Loans		1,000,751,792	796,568,451
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans		9,694,041	6,305,772
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans		24,084,953	24,763,040
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans
Commercial Real Estate Portfolio Segment [Member]
Loans		1,157,855,663	1,093,458,860
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans		327,144,766	332,387,621
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans		168,992,704	165,149,491
Commercial Real Estate Portfolio Segment [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans		661,718,193	595,921,748
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans		313,179,076	314,447,662
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Construction Loans [Member]
Loans		161,772,865	158,108,465
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans		639,045,018	582,854,048
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans		9,155,153	7,559,380
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Construction Loans [Member]
Loans		2,167,999	1,780,000
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans		6,297,895	4,437,122
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans		4,810,537	10,380,369
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Construction Loans [Member]
Loans		5,051,840	5,261,026
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans		16,375,280	8,630,578
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans			210
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] | Construction Loans [Member]
Loans
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans
Commercial and Commercial Real Estate Portfolio Segments [Member]
Loans		$ 2,192,386,449	$ 1,921,096,123
As a % of Total		100.00%	100.00%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Pass [Member]
Loans		$ 2,114,748,751	$ 1,851,978,626
As a % of Total		96.45%	96.40%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Special Mention [Member]
Loans		$ 27,315,088	$ 20,082,274
As a % of Total		1.25%	1.05%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Substandard [Member]
Loans		$ 50,322,610	$ 49,035,013
As a % of Total		2.30%	2.55%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Doubtful [Member]
Loans			$ 210
As a % of Total			0.00%

[1] 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.