NOTE 4 - LOANS/LEASES RECEIVABLE - Aging of the Loan Lease Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current	$ 3,587,169	$ 3,698,177
Accruing Past Due 90 Days or More		632
Financing Receivable, Recorded Investment, Nonaccrual Status	8,231	14,260
Loans and leases	$ 3,602,414	$ 3,723,630
Current as a percentage of total loan/lease portfolio	99.58%	99.32%
Accruing past due 90 days or more as a percentage of total loan/lease portfolio		0.02%
Nonaccrual Loans/Leases as a percentage of total loan/lease portfolio	0.22%	0.38%
Loans and leases as a percentage of total loan/lease portfolio	100.00%	100.00%
Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	$ 5,746	$ 9,053
Past due as a percentage of total loan/lease portfolio	0.16%	0.24%
Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	$ 1,268	$ 1,508
Past due as a percentage of total loan/lease portfolio	0.04%	0.04%
Commercial Portfolio Segment [Member]
Current	$ 1,466,347	$ 1,423,406
Accruing Past Due 90 Days or More		389
Financing Receivable, Recorded Investment, Nonaccrual Status	1,318	4,088
Loans and leases	1,469,978	1,429,410
Commercial Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	2,067	930
Commercial Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	246	597
Commercial Real Estate Portfolio Segment [Member]
Loans and leases	1,687,922	1,766,111
Commercial Real Estate Portfolio Segment [Member] \| Owner Occupied Commercial Real Estate Loans [Member]
Current	440,668	500,138
Accruing Past Due 90 Days or More		107
Financing Receivable, Recorded Investment, Nonaccrual Status	178	216
Loans and leases	441,122	500,654
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Current	368,422	234,704
Financing Receivable, Recorded Investment, Nonaccrual Status		319
Loans and leases	369,123	236,787
Commercial Real Estate Portfolio Segment [Member] \| Other Non-owner Occupied Commercial Real Estate Loans [Member]
Current	872,591	1,022,664
Financing Receivable, Recorded Investment, Nonaccrual Status	3,595	5,522
Loans and leases	877,677	1,028,670
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member] \| Owner Occupied Commercial Real Estate Loans [Member]
Past Due	276
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member] \| Construction Loans [Member]
Past Due	701	1,764
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member] \| Other Non-owner Occupied Commercial Real Estate Loans [Member]
Past Due	1,491	484
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member] \| Owner Occupied Commercial Real Estate Loans [Member]
Past Due		193
Finance Leases Portfolio Segment [Member]
Current	89,776	114,078
Financing Receivable, Recorded Investment, Nonaccrual Status	1,397	1,761
Loans and leases	92,307	117,969
Finance Leases Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	816	1,642
Finance Leases Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	318	488
Residential Portfolio Segment [Member]
Current	243,785	284,844
Accruing Past Due 90 Days or More		89
Financing Receivable, Recorded Investment, Nonaccrual Status	1,120	1,743
Loans and leases	245,667	290,759
Residential Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	58	3,877
Residential Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	704	206
Consumer Portfolio Segment [Member]
Current	105,580	118,343
Accruing Past Due 90 Days or More		47
Financing Receivable, Recorded Investment, Nonaccrual Status	623	611
Loans and leases	106,540	119,381
Consumer Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	$ 337	356
Consumer Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due		$ 24

Reflects the percentage derived from dividing loans accruing past due 90 days or more by total loans.

No definition available.

Name:	qcrh_PercentageOfAccruingPastDue90DaysOrMoreToTotalLoanLeasePortfolio
Namespace Prefix:	qcrh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Reflects the percentage derived from dividing current loans by total loans.

+ References

No definition available.

+ Details

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

- Definition

Reflects the percentage derived from dividing nonaccrual loans by total loans.

+ References

No definition available.

+ Details

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

- Definition

Reflects the percentage derived from dividing past due loans by total loans.

+ References

No definition available.

+ Details

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

- Definition

Amount of financing receivable 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable not past due.

+ References

+ Details

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

- Definition

Amount of financing receivable on nonaccrual status.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

+ Details

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

- Definition

Amount of financing receivable past due.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919253-210447

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953401-111524

+ Details

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

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

+ Details

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

- Definition

Reflects the percentage derived from dividing impaired loans on which interest has ceased to be accrued by total loans.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=qcrh_OwnerOccupiedCommercialRealEstateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=qcrh_OtherNonownerOccupiedCommercialRealEstateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_FinanceLeasesPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: