Note 6 - Fair Value - Quantitative Information About Level Fair Value Measurements (Details)	18 Months Ended
Jun. 30, 2018 USD ($) item	Dec. 31, 2017 USD ($)
Transfers of assets or liabilities between Levels 1, 2 and 3 \| $	$ 0
Impaired Loans Leases [Member]
Fair value \| $	$ 4,674,218	$ 8,972,337
Valuation technique	qcrh:ValuationTechniqueAppraisalOfCollateralMember
Unobservable input	us-gaap:MeasurementInputAppraisedValueMember
Impaired Loans Leases [Member] \| Minimum
Impaired loans/leases, measurement input	(10.00)
Impaired Loans Leases [Member] \| Maximum
Impaired loans/leases, measurement input	(30.00)
Other Real Estate Owned [Member]
Fair value \| $	$ 13,770,025	$ 14,642,973
Valuation technique, OREO	qcrh:ValuationTechniqueAppraisalOfCollateralMember
Unobservable input, OREO	us-gaap:MeasurementInputAppraisedValueMember
Other Real Estate Owned [Member] \| Minimum
OREO, measurement input	0.00
Other Real Estate Owned [Member] \| Maximum
OREO, measurement input	(35.00)

The measurement input for impaired loans.

No definition available.

Name:	qcrh_ImpairedLoansMeasurementInput
Namespace Prefix:	qcrh_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of assets or liabilities transferred between Levels 1, 2 and 3 of the fair value hierarchy.

+ References

No definition available.

+ Details

Name:	qcrh_TransfersOfAssetsOrLiabilitiesBetweenLevelsOneTwoAndThree
Namespace Prefix:	qcrh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-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

+ Details

Name:	us-gaap_AlternativeInvestmentMeasurementInputExtensibleList
Namespace Prefix:	us-gaap_
Data Type:	srt-types:extensibleListItemType
Balance Type:	na
Period Type:	instant

- Definition

Indicates valuation technique for measuring alternative investment.

+ References

+ Details

Name:	us-gaap_AlternativeInvestmentValuationTechniqueExtensibleList
Namespace Prefix:	us-gaap_
Data Type:	srt-types:extensibleListItemType
Balance Type:	na
Period Type:	instant

- 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

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

Name:	us-gaap_OtherRealEstateOwnedMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Indicates measurement input for real estate owned by financial institution which is not directly related to its business.

+ References

+ Details

Name:	us-gaap_OtherRealEstateOwnedMeasurementInputExtensibleList
Namespace Prefix:	us-gaap_
Data Type:	srt-types:extensibleListItemType
Balance Type:	na
Period Type:	instant

- Definition

Indicates valuation technique for measuring real estate owned by financial institution which is not directly related to its business.

+ References

+ Details

Name:	us-gaap_OtherRealEstateOwnedValuationTechniqueExtensibleList
Namespace Prefix:	us-gaap_
Data Type:	srt-types:extensibleListItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_FairValueByAssetClassAxis=qcrh_ImpairedLoansLeasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=qcrh_OtherRealEstateOwnedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: