Percentage of aggregate consideration paid for by equity interest issued or issuable to acquire entity.

No definition available.

Name:	qcrh_BusinessAcquisitionEquityInterestIssuedOrIssuablePercentageOfAggregateConsideration
Namespace Prefix:	qcrh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The period over which goodwill is deductible for tax purposes.

+ References

No definition available.

+ Details

Name:	qcrh_BusinessAcquisitionGoodwillExpectedTaxDeductibleAmountTerm
Namespace Prefix:	qcrh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of banking branches owned.

+ References

No definition available.

+ Details

Name:	qcrh_NumberOfBranches
Namespace Prefix:	qcrh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of aggregate consideration for the cash outflow to acquire entity.

+ References

No definition available.

+ Details

Name:	qcrh_PaymentsToAcquireBusinessesGrossPercentageOfAggregateConsideration
Namespace Prefix:	qcrh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e1043-128460

+ Details

Name:	us-gaap_BusinessCombinationAcquisitionRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessCombinationIntegrationRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=qcrh_GuarantyBankAndTrustCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 2 - Sales/Mergers/Acquisitions - Guaranty Bank and Trust (Details) $ / shares in Units, $ in Thousands			12 Months Ended
	Oct. 01, 2017 location shares	Sep. 27, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 29, 2017 $ / shares
Business Acquisition [Line Items]
Debt Instrument, Face Amount			$ 40,210	$ 40,210
Business Combination, Acquisition Related Costs				1,795	$ 1,069
Post-acquisition compensation, transition and integration costs			$ 3,582	$ 2,086	4,310
Guaranty Bank and Trust Company [Member]
Business Acquisition [Line Items]
Number Of Branches \| location	5
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Percentage of total consideration consisting of common stock	79.00%
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares \| shares	678,670
Percentage of total consideration paid in cash	21.00%
Share Price \| $ / shares						$ 45.50
Debt Instrument, Face Amount		$ 7,000
Repayment period (in years)		4 years
Term over which goodwill is deductible for tax purposes	15 years
Business Combination, Acquisition Related Costs					805,000
Post-acquisition compensation, transition and integration costs					$ 3,100