Note 21 - Fair Value - Quantitative Information About Level Fair Value Measurements (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($)
Fair value		$ 19,784,866	$ 23,615,310
Amount of fair value assets transfered from Level 1 to Level 2		0	0
Amount of fair value assets transfered from Level 2 to Level 1	$ 0	0
Amount of fair value liabilities transfered from Level 1 to Level 2		0	0
Amount of fair value liabilities transfered from Level 2 to Level 1		0	0
Impaired Loans Leases [Member]
Fair value		$ 9,656,912	8,972,337
Valuation technique		qcrh:ValuationTechniqueAppraisalOfCollateralMember
Unobservable input		us-gaap:MeasurementInputAppraisedValueMember
Impaired Loans Leases [Member] \| Minimum
Impaired loans/leases, measurement input \| item		(10.00)
Impaired Loans Leases [Member] \| Maximum
Impaired loans/leases, measurement input \| item		(30.00)
Other Securities
Fair value		$ 10,127,954	14,642,973
Valuation technique		qcrh:ValuationTechniqueAppraisalOfCollateralMember
Unobservable input		us-gaap:MeasurementInputAppraisedValueMember
Other Securities \| Minimum
OREO, measurement input \| item		0.00
Other Securities \| Maximum
OREO, measurement input \| item		(35.00)
Other Real Estate Owned [Member]
Fair value		$ 10,127,954	14,642,973
Fair Value, Inputs, Level 3 [Member]
Fair value		19,784,866	23,615,310
Fair Value, Inputs, Level 3 [Member] \| Impaired Loans Leases [Member]
Fair value		9,656,912	8,972,337
Fair Value, Inputs, Level 3 [Member] \| Other Real Estate Owned [Member]
Fair value		$ 10,127,954	$ 14,642,973

The measurement input for impaired loans.

No definition available.

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- Definition

Indicates measurement input for alternative investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14210-108612

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- Definition

Indicates valuation technique for measuring alternative investment.

+ References

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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Period Type:	instant

- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Value of input used to measure real estate owned by financial institution by financial institution which is not directly related to its business.

+ References

+ Details

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